Universal Decimal Classification

The UDC is an analytico-synthetic and faceted classification system featuring detailed vocabulary and syntax that enables powerful content indexing and information retrieval in large collections. Since 1991, the UDC has been owned and managed by the UDC Consortium, a non-profit international association of publishers with headquarters in The Hague, Netherlands.

Unlike other library classification schemes that started their life as national systems, the UDC was conceived and maintained as an international scheme. Its translation into other languages started at the beginning of the 20th century and has since been published in various printed editions in over 40 languages. UDC Summary, an abridged Web version of the scheme, is available in over 50 languages. The classification has been modified and extended over the years to cope with increasing output in all areas of human knowledge, and is still under continuous review to take account of new developments.

Albeit originally designed as an indexing and retrieval system, due to its logical structure and scalability, UDC has become one of the most widely used knowledge organization systems in libraries, where it is used for either shelf arrangement, content indexing or both. UDC codes can describe any type of document or object to any desired level of detail. These can include textual documents and other media such as films, video and sound recordings, illustrations, maps as well as realia such as museum objects.

 

The UDC was developed by the Belgian bibliographers Paul Otlet and Henri La Fontaine at the end of the 19th century. In 1895, they created the Universal Bibliographic Repertory (Répertoire Bibliographique Universel) (RBU) which was intended to become a comprehensive classified index to all published information. The idea that the RBU should take the form of a card catalogue came from the young American zoologist Herbert Haviland Field, who was at the time himself setting up a bibliographical agency in Zurich, the Concilium Bibliographicum. A means of arranging the entries would be needed, and Otlet, having heard of the Dewey Decimal Classification, wrote to Melvil Dewey and obtained permission to translate it into French. The idea outgrew the plan of mere translation, and a number of radical innovations were made, adapting the purely enumerative classification (in which all the subjects envisaged are already listed and coded) into one which allows for synthesis (that is, the construction of compound numbers to denote interrelated subjects that could never be exhaustively foreseen); various possible relations between subjects were identified, and symbols assigned to represent them. In its first edition in French "Manuel du Répertoire bibliographique universel" (1905), the UDC already included many features that were revolutionary in the context of knowledge classifications: tables of generally applicable (aspect-free) concepts—called common auxiliary tables; a series of special auxiliary tables with specific but re-usable attributes in a particular field of knowledge; an expressive notational system with connecting symbols and syntax rules to enable coordination of subjects and the creation of a documentation language proper.

The Universal Bibliographic Repertory itself has developed into a remarkable information resource. In the period before World War I it grew to more than eleven million records. The catalogue and its content organized by UDC can still be seen in Mundaneum in Mons, Belgium (in 2013 recommended for inclusion in the UNESCO Memory of the World Register).

UDC is used in around 150,000 libraries in 130 countries and in many bibliographical services which require detailed content indexing. In a number of countries it is the main classification system for information exchange and is used in all types of libraries: public, school, academic and special libraries.

UDC is also used in national bibliographies of around 30 countries. Examples of large databases indexed by UDC include:

NEBIS (The Network of Libraries and Information Centers in Switzerland) — 2.6 million records
COBIB.SI (Slovenian National Union Catalogue) — 3.5 million records
Hungarian National Union Catalogue (MOKKA) — 2.9 million records
VINITI RAS database (All-Russian Scientific and Technical Information Institute of Russian Academy of Science) with 28 million records
Meteorological & Geoastrophysical Abstracts (MGA) with 600 journal titles
PORBASE (Portuguese National Bibliography) with 1.5 million records

UDC has traditionally been used for the indexing of scientific articles which was an important source of information of scientific output in the period predating electronic publishing. Collections of research articles in many countries covering decades of scientific output contain UDC codes. Examples of journal articles indexed by UDC:

UDC code 663.12:57.06 in the article "Yeast Systematics: from Phenotype to Genotype" in the journal Food Technology and Biotechnology (ISSN 1330-9862)
UDC code 37.037:796.56, provided in the article "The game method as means of interface of technical-tactical and psychological preparation in sports orienteering" in the Russian journal "Pedagogico-psychological and medico-biological problems of the physical culture and sport" (ISSN 2070-4798).
UDC code 621.715:621.924:539.3 in the article Residual Stress in Shot-Peened Sheets of AIMg4.5Mn Alloy - in the journal Materials and technology (ISSN 1580-2949).

The design of UDC lends itself to machine readability, and the system has been used both with early automatic mechanical sorting devices, and modern library OPACs. Since 1993, a standard version of UDC has been maintained and distributed in a database format: UDC Master Reference File (UDC MRF) which is updated and released regularly. The 2011 version of the MRF (released in 2012) contains over 70,000 classes. In the past full printed editions used to have around 220,000 subdivisions.

Notation

A notation is a code commonly used in classification schemes to represent a class, i.e. a subject and its position in the hierarchy, to enable mechanical sorting and filing of subjects. UDC uses Arabic numerals arranged decimally. Every number is thought of as a decimal fraction with the initial decimal point omitted, which determines the filing order. An advantage of decimal notational systems is that they are infinitely extensible, and when new subdivisions are introduced, they need not disturb the existing allocation of numbers. For ease of reading, a UDC notation is usually punctuated after every third digit:

In UDC the notation has two features that make the scheme easier to browse and work with:

• hierarchically expressive – the longer the notation, the more specific the class: removing the final digit automatically produces a broader class code.
• syntactically expressive – when UDC codes are combined, the sequence of digits is interrupted by a precise type of punctuation sign which indicates that the expression is a combination of classes rather than a simple class e.g. the colon in 34:32 indicates that there are two distinct notational elements: 34 Law. Jurisprudence and 32 Politics; the closing and opening parentheses and double quotes in the following code 913(574.22)"19"(084.3) indicate four separate notational elements: 913 Regional geography, (574.22) North Kazakhstan (Soltüstik Qazaqstan); "19" 20th century and (084.3) Maps (document form)

Basic features and syntax

UDC is an analytico-synthetic and faceted classification. It allows an unlimited combination of attributes of a subject and relationships between subjects to be expressed. UDC codes from different tables can be combined to present various aspects of document content and form, e.g. 94(410)"19"(075) History (main subject) of United Kingdom (place) in 20th century (time), a textbook (document form). Or: 37:2 Relationship between Education and Religion. Complex UDC expressions can be accurately parsed into constituent elements.

UDC is also a disciplinary classification covering the entire universe of knowledge. This type of classification can also be described as aspect or perspective, which means that concepts are subsumed and placed under the field in which they are studied. Thus, the same concept can appear in different fields of knowledge. This particular feature is usually implemented in UDC by re-using the same concept in various combinations with the main subject, e.g. a code for language in common auxiliaries of language is used to derive numbers for ethnic grouping, individual languages in linguistics and individual literatures. Or, a code from the auxiliaries of place, e.g. (410) United Kingdom, uniquely representing the concept of United Kingdom can be used to express 911(410) Regional geography of United Kingdom and 94(410) History of United Kingdom.

Organization of classes

Concepts are organized in two kinds of tables in UDC:

• Common auxiliary tables (including certain auxiliary signs). These tables contain facets of concepts representing general recurrent characteristics, applicable over a range of subjects throughout the main tables, including notions such as place, language of the text and physical form of the document, which may occur in almost any subject. UDC numbers from these tables, called common auxiliaries are simply added at the end of the number for the subject taken from the main tables. There are over 15,000 common auxiliaries in UDC.
• The main tables or main schedules containing the various disciplines and branches of knowledge are arranged in 9 main classes, numbered from 0 to 9 (with class 4 being vacant). At the beginning of each class there are also series of special auxiliaries, which express aspects that are recurrent within this specific class. Main tables in UDC contain more than 60,000 subdivisions.

Main classes

• 0 Science and Knowledge. Organization. Computer Science. Information Science. Documentation. Librarianship. Institutions. Publications
• 1 Philosophy. Psychology
• 2 Religion. Theology
• 3 Social Sciences
• 4 vacant
• 5 Mathematics. Natural Sciences
• 6 Applied Sciences. Medicine, Technology
• 7 The Arts. Entertainment. Sport
• 8 Linguistics. Literature
• 9 Geography. History

The vacant class 4 is the result of a planned schedule expansion. This class was freed by moving linguistics into class 8 in the 1960s to make space for future developments in the rapidly expanding fields of knowledge; primarily natural sciences and technology.

Common auxiliary tables

Common auxiliaries are aspect-free concepts that can be used in combination with any other UDC code from the main classes or with other common auxiliaries. They have unique notational representations that makes them stand out in complex expressions. Common auxiliary numbers always begin with a certain symbol known as a facet indicator, e.g. = (equal sign) always introduces concepts representing the language of a document; (0...) numbers enclosed in parentheses starting with zero always represent a concept designating document form. Thus (075) Textbook and =111 English can be combined to express, e.g.(075)=111 Textbooks in English, and when combined with numbers from the main UDC tables they can be used as follows: 2(075)=111 Religion textbooks in English, 51(075)=111 Mathematics textbooks in English etc.

• =...Common auxiliaries of language. Table 1c
• (0...)Common auxiliaries of form. Table 1d
• (1/9)Common auxiliaries of place. Table 1e
• (=...)Common auxiliaries of human ancestry, ethnic grouping and nationality. Table 1f
• "..."Common auxiliaries of time. Table 1g helps to make minute division of time e.g.: "1993-1996"
• -0...Common auxiliaries of general characteristics: Properties, Materials, Relations/Processes and Persons. Table 1k.
• -02Common auxiliaries of properties. Table 1k
• -03Common auxiliaries of materials. Table 1k
• -04Common auxiliaries of relations, processes and operations. Table 1k
• -05Common auxiliaries of persons and personal characteristics. Table 1k this table is repeated

Connecting signs

In order to preserve the precise meaning and enable accurate parsing of complex UDC expressions, a number of connecting symbols are made available to relate and extend UDC numbers. These are:

UDC classes in this outline are taken from the Multilingual Universal Decimal Classification Summary (UDCC Publication No. 088) released by the UDC Consortium under the Creative Commons Attribution Share Alike 3.0 license (first release 2009, subsequent update 2012).

Main tables

0 Science and knowledge. Organization. Computer science. Information. Documentation. Librarianship. Institution. Publications

 00          Prolegomena. Fundamentals of knowledge and culture. Propaedeutics  001         Science and knowledge in general. Organization of intellectual work  002         Documentation. Books. Writings. Authorship  003         Writing systems and scripts  004         Computer science and technology. Computing  004.2       Computer architecture  004.3       Computer hardware  004.4       Software  004.5       Human-computer interaction  004.6       Data  004.7       Computer communication  004.8       Artificial intelligence  004.9       Application-oriented computer-based techniques  005         Management  005.1       Management Theory  005.2       Management agents. Mechanisms. Measures  005.3       Management activities  005.5       Management operations. Direction  005.6       Quality management. Total quality management (TQM)  005.7       Organizational management (OM)  005.9       Fields of management  005.92      Records management  005.93      Plant management. Physical resources management  005.94      Knowledge management  005.95/.96  Personnel management. Human Resources management  006         Standardization of products, operations, weights, measures and time  007         Activity and organizing. Information. Communication and control theory generally (cybernetics)  008         Civilization. Culture. Progress     01          Bibliography and bibliographies. Catalogues  02          Librarianship  030         General reference works (as subject)  050         Serial publications, periodicals (as subject)  06          Organizations of a general nature  069         Museums  070         Newspapers (as subject). The Press. Outline of journalism  08          Polygraphies. Collective works (as subject)  09          Manuscripts. Rare and remarkable works (as subject) 

1 Philosophy. Psychology

 101        Nature and role of philosophy  11         Metaphysics  111        General metaphysics. Ontology  122/129    Special Metaphysics  13         Philosophy of mind and spirit. Metaphysics of spiritual life  14         Philosophical systems and points of view  141        Kinds  of viewpoint. Including:  Monism. Dualism. Pluralism. Ontological Materialism. Metaphysical Idealism. Platonism, etc.  159.9      Psychology  159.91     Psychophysiology (physiological psychology). Mental physiology  159.92     Mental development and capacity. Comparative psychology  159.93     Sensation. Sensory perception  159.94     Executive functions  159.95     Higher mental processes  159.96     Special mental states and processes  159.97     Abnormal psychology  159.98     Applied psychology (psychotechnology) in general  16         Logic. Epistemology. Theory of knowledge. Methodology of logic  17         Moral philosophy. Ethics. Practical philosophy 

2 Religion. Theology

The UDC tables for religion are fully faceted. Indicated in italics below, are special auxiliary numbers that can be used to express attributes (facets) of any specific faith. Any special number can be combined with any religion e.g. -5 Worship can be used to express e.g. 26-5 Worship in Judaism, 27-5 Worship in Christianity, 24-5 Worship in Buddhism. The complete special auxiliary tables contain around 2000 subdivisions of various attributes that can be attached to express various aspects of individual faiths to a great level of specificity allowing equal level of detail for every religion.

 2-1/-9Special auxiliary subdivision for religion  2-1Theory and philosophy of religion. Nature of religion. Phenomenon of religion  2-2Evidences of religion  2-3Persons in religion  2-4Religious activities. Religious practice  2-5Worship broadly. Cult. Rites and ceremonies  2-6Processes in religion  2-7Religious organization and administration  2-8Religions characterised by various properties  2-9History of the faith, religion, denomination or church  21/29Religious systems. Religions and faiths  21Prehistoric and primitive religions  22Religions originating in the Far East  23Religions originating in Indian sub-continent. Hindu religion in the broad sense  24Buddhism  25Religions of antiquity. Minor cults and religions  26Judaism  27Christianity  28Islam  29Modern spiritual movements 

3 Social sciences

 303   Methods of the social sciences  304Social questions. Social practice. Cultural practice. Way of life (Lebensweise)  305Gender studies  308Sociography. Descriptive studies of society (both qualitative and quantitative)  311Statistics as a science. Statistical theory  314/316 Society  314Demography. Population studies  316Sociology  32Politics  33Economics. Economic science  34Law. Jurisprudence  35Public administration. Government. Military affairs  36Safeguarding the mental and material necessities of life  37Education  39Cultural anthropology. Ethnography. Customs. Manners. Traditions. Way of life 

4 Currently Vacant

This section is currently vacant.

5 Mathematics. Natural sciences

 502/504  Environmental science. Conservation of natural resources. Threats to the environment and protection against them  502The environment and its protection  504Threats to the environment  51Mathematics  510Fundamental and general considerations of mathematics  511Number theory  512Algebra  514Geometry  517Analysis  519.1Combinatorial analysis. Graph theory  519.2Probability. Mathematical statistics  519.6Computational mathematics. Numerical analysis  519.7Mathematical cybernetics  519.8Operational research (OR): mathematical theories and methods  52Astronomy. Astrophysics. Space research. Geodesy  53Physics  531/534  Mechanics  535Optics  536Heat. Thermodynamics. Statistical physics  537Electricity. Magnetism. Electromagnetism  538.9Condensed matter physics. Solid state physics  539Physical nature of matter  54Chemistry. Crystallography. Mineralogy  542Practical laboratory chemistry. Preparative and experimental chemistry  543Analytical chemistry  544Physical chemistry  546Inorganic chemistry  547Organic chemistry  548/549 Mineralogical sciences. Crystallography. Mineralogy  55Earth sciences. Geological sciences  56Paleontology  57Biological sciences in general  58Botany  59Zoology 

6 Applied sciences. Medicine. Technology

Class 6 occupies the largest proportion of UDC schedules. It contains over 44,000 subdivisions. Each specific field of technology or industry usually contains more than one special auxiliary table with concepts needed to express operations, processes, materials and products. As a result, UDC codes are often created through the combination of various attributes. Equally, some parts of this class enumerate concepts to a great level of detail e.g. 621.882.212 Hexagon screws with additional shapes. Including: Flank screws. Collar screws. Cap screws

 60    Biotechnology  61Medical sciences  611/612 Human biology  613Hygiene generally. Personal health and hygiene  614Public health and hygiene. Accident prevention  615Pharmacology. Therapeutics. Toxicology  616Pathology. Clinical medicine  617Surgery. Orthopaedics. Ophthalmology  618Gynaecology. Obstetrics  62Engineering. Technology in general  620Materials testing. Commercial materials. Power stations. Economics of energy  621Mechanical engineering in general. Nuclear technology. Electrical engineering. Machinery  622Mining  623Military engineering  624Civil and structural engineering in general  625Civil engineering of land transport. Railway engineering. Highway engineering  626/627  Hydraulic engineering and construction. Water (aquatic) structures  629Transport vehicle engineering  63Agriculture and related sciences and techniques. Forestry. Farming. Wildlife exploitation  630Forestry  631/635Farm management. Agronomy. Horticulture  633/635Horticulture in general. Specific crops  636Animal husbandry and breeding in general. Livestock rearing. Breeding of domestic animals  64Home economics. Domestic science. Housekeeping  65Communication and transport industries. Accountancy. Business management. Public relations  654Telecommunication and telecontrol (organization, services)  655Graphic industries. Printing. Publishing. Book trade  656Transport and postal services. Traffic organization and control  657Accountancy  658Business management, administration. Commercial organization  659Publicity. Information work. Public relations  66Chemical technology. Chemical and related industries  67Various industries, trades and crafts  68Industries, crafts and trades for finished or assembled articles  69Building (construction) trade. Building materials. Building practice and procedure 

7 The arts. Recreation. Entertainment. Sport

 7.01/.09Special auxiliary subdivision for the arts  7.01Theory and philosophy of art. Principles of design, proportion, optical effect  7.02Art technique. Craftsmanship  7.03Artistic periods and phases. Schools, styles, influences  7.04Subjects for artistic representation. Iconography. Iconology  7.05Applications of art (in industry, trade, the home, everyday life)  7.06Various questions concerning art  7.07Occupations and activities associated with the arts and entertainment  7.08Characteristic features, forms, combinations etc. (in art, entertainment and sport)  7.091Performance, presentation (in original medium)  71Physical planning. Regional, town and country planning. Landscapes, parks, gardens  72Architecture  73Plastic arts  74Drawing. Design. Applied arts and crafts  745/749Industrial and domestic arts and crafts. Applied arts  75Painting  76Graphic art, printmaking. Graphics  77Photography and similar processes  78Music  79Recreation. Entertainment. Games. Sport  791Cinema. Films (motion pictures)  792Theatre. Stagecraft. Dramatic performances  793Social entertainments and recreations. Art of movement. Dance  794Board and table games (of thought, skill and chance)  796Sport. Games. Physical exercises  797Water sports. Aerial sports  798Riding and driving. Horse and other animal sports  799Sport fishing. Sport hunting. Shooting and target sports 

8 Language. Linguistics. Literature

Tables for class 8 are fully faceted and details are expressed through combination with common auxiliaries of language (Table 1c) and a series of special auxiliary tables to indicate other facets or attributes in Linguistics or Literature. As a result, this class allows for great specificity in indexing although the schedules themselves occupy very little space in UDC. The subdivisions of e.g. 811 Languages or 821 Literature are derived from common auxiliaries of language =1/=9 (Table 1c) by substituting a point for the equals sign, e.g. 811.111 English language (as a subject of a linguistic study) and 821.111 English literature derives from =111 English language. Common auxiliaries of place and time are also frequently used in this class to express place and time facets of Linguistics or Literature, e.g. 821.111(71)"18" English literature of Canada in 19th century

 80General questions relating to both linguistics and literature. Philology  801Prosody. Auxiliary sciences and sources of philology  808Rhetoric. The effective use of language    81Linguistics and languages  81`1/`4Special auxiliary subdivision for subject fields and facets of linguistics and languages  81`1General linguistics  81`2Theory of signs. Theory of translation. Standardization. Usage. Geographical linguistics  81`3Mathematical and applied linguistics. Phonetics. Graphemics. Grammar. Semantics. Stylistics  81`4Text linguistics, Discourse analysis. Typological linguistics  81`42Text linguistics. Discourse analysis  81`44Typological linguistics  811Languages        Derived from the common auxiliaries of language =1/=9 (Table 1c) by replacing the equal sign = with prefix 811. e.g. =111 English becomes 811.111 Linguistics of English language  811.1/.9All languages natural or artificial  811.1/.8Individual natural languages  811.1/.2Indo-European languages  811.21/.22Indo-Iranian languages  811.3Dead languages of unknown affiliation. Caucasian languages  811.4Afro-Asiatic, Nilo-Saharan, Congo-Kordofanian, Khoisan languages  811.5Ural-Altaic, Palaeo-Siberian, Eskimo-Aleut, Dravidian and Sino-Tibetan languages. Japanese. Korean. Ainu  811.6Austro-Asiatic languages. Austronesian languages  811.7Indo-Pacific (non-Austronesian) languages. Australian languages  811.8American indigenous languages  811.9Artificial languages  82Literature  82-1/-9Special auxiliary subdivision for literary forms, genres  82-1Poetry. Poems. Verse  82-2Drama. Plays  82-3Fiction. Prose narrative  82-31Novels. Full-length stories  82-32Short stories. Novellas  82-4Essays  82-5Oratory. Speeches  82-6Letters. Art of letter-writing. Correspondence. Genuine letters  82-7Prose satire. Humour, epigram, parody  82-8Miscellanea. Polygraphies. Selections  82-9Various other literary forms  82-92Periodical literature. Writings in serials, journals, reviews  82-94History as literary genre. Historical writing. Historiography. Chronicles. Annals. Memoirs  82.02/.09Special auxiliary subdivision for theory, study and technique of literature  82.02Literary schools, trends and movements  82.09Literary criticism. Literary studies  82.091Comparative literary studies. Comparative literature  821Literatures of individual languages and language families        Derived from the common auxiliaries of language =1/=9 (Table 1c) by replacing the equal sign = with prefix 821. e.g. =111 English becomes 821.111 English literature 

9 Geography. Biography. History

Tables for Geography and History in UDC are fully faceted and place, time and ethnic grouping facets are expressed through combination with common auxiliaries of place (Table 1d), ethnic grouping (Table 1f) and time (Table 1g)

 902/908Archaeology. Prehistory. Cultural remains. Area studies  902Archaeology  903Prehistory. Prehistoric remains, artifacts, antiquities  904Cultural remains of historical times  908Area studies. Study of a locality  91Geography. Exploration of the Earth and of individual countries. Travel. Regional geography  910General questions. Geography as a science. Exploration. Travel  911General geography. Science of geographical factors (systematic geography). Theoretical geography  911.2Physical geography  911.3Human geography (cultural geography). Geography of cultural factors  911.5/.9Theoretical geography  912Nonliterary, nontextual representations of a region  913Regional geography  92Biographical studies. Genealogy. Heraldry. Flags  929Biographical studies  929.5Genealogy  929.6Heraldry  929.7Nobility. Titles. Peerage  929.9Flags. Standards. Banners  93/94History  930Science of history. Historiography  930.1History as a science  930.2Methodology of history. Ancillary historical sciences  930.25Archivistics. Archives (including public and other records)  930.85History of civilization. Cultural history  94General 

Common auxiliary tables

Common auxiliaries of language. Table 1c

 =1/=9Languages (natural and artificial)  =1/=8Natural languages  =1/=2Indo-European languages  =1Indo-European languages of Europe  =11Germanic languages  =12Italic languages  =13Romance languages  =14Greek (Hellenic)  =15Celtic languages  =16Slavic languages  =17Baltic languages  =18Albanian  =19Armenian  =2Indo-Iranian, Nuristani (Kafiri) and dead Indo-European languages  =21/=22Indo-Iranian languages  =21Indic languages  =22Iranian languages  =29Dead Indo-European languages (not listed elsewhere)  =3Dead languages of unknown affiliation. Caucasian languages  =34Dead languages of unknown affiliation, spoken in the Mediterranean and Near East (except Semitic)  =35Caucasian languages  =4Afro-Asiatic, Nilo-Saharan, Congo-Kordofanian, Khoisan languages  =41Afro-Asiatic (Hamito-Semitic) languages  =42Nilo-Saharan languages  =43Congo-Kordofanian (Niger-Kordofanian) languages  =45Khoisan languages  =5Ural-Altaic, Palaeo-Siberian, Eskimo-Aleut, Dravidian and Sino-Tibetan languages. Japanese. Korean. Ainu  =51Ural-Altaic languages  =521Japanese  =531Korean  =541Ainu  =55Palaeo-Siberian languages  =56Eskimo-Aleut languages  =58Sino-Tibetan languages  =6Austro-Asiatic languages. Austronesian languages  =61Austro-Asiatic languages  =62Austronesian languages  =7Indo-Pacific (non-Austronesian) languages. Australian languages  =71Indo-Pacific (non-Austronesian) languages  =72Australian languages  =8American indigenous languages  =81Indigenous languages of Canada, USA and Northern-Central Mexico  =82Indigenous languages of western North American Coast, Mexico and Yucatán  =84/=88Central and South American indigenous languages  =84Ge-Pano-Carib languages. Macro-Chibchan languages  =85Andean languages. Equatorial languages  =86Chaco languages. Patagonian and Fuegian languages  =88Isolated, unclassified Central and South American indigenous languages  =9Artificial languages  =92Artificial languages for use among human beings. International auxiliary languages (interlanguages)  =93Artificial languages used to instruct machines. Programming languages. Computer languages 

(0...) Common auxiliaries of form. Table 1d

 (0.02/.08)Special auxiliary subdivision for document form  (0.02)Documents according to physical, external form  (0.03)Documents according to method of production  (0.032)Handwritten documents (autograph, holograph copies). Manuscripts. Pictorial documents (drawings, paintings)  (0.034)Machine-readable documents  (0.04)Documents according to stage of production  (0.05)Documents for particular kinds of user  (0.06)Documents according to level of presentation and availability  (0.07)Supplementary matter issued with a document  (0.08)Separately issued supplements or parts of documents  (01)Bibliographies  (02)Books in general  (03)Reference works  (04)Non-serial separates. Separata  (041)Pamphlets. Brochures  (042)Addresses. Lectures. Speeches  (043)Theses. Dissertations  (044)Personal documents. Correspondence. Letters. Circulars  (045)Articles in serials, collections etc. Contributions  (046)Newspaper articles  (047)Reports. Notices. Bulletins  (048)Bibliographic descriptions. Abstracts. Summaries. Surveys  (049)Other non-serial separates  (05)Serial publications. Periodicals  (06)Documents relating to societies, associations, organizations  (07)Documents for instruction, teaching, study, training  (08)Collected and polygraphic works. Forms. Lists. Illustrations. Business publications  (09)Presentation in historical form. Legal and historical sources  (091)Presentation in chronological, historical form. Historical presentation in the strict sense  (092)Biographical presentation  (093)Historical sources  (094)Legal sources. Legal documents 

(1/9) Common auxiliaries of place. Table 1e

 (1)Place and space in general. Localization. Orientation  (1-0/-9)Special auxiliary subdivision for boundaries and spatial forms of various kinds  (1-0)Zones  (1-1)Orientation. Points of the compass. Relative position  (1-11)East. Eastern  (1-13)South. Southern  (1-14)South-west. South-western  (1-15)West. Western  (1-17)North. Northern  (1-19)Relative location, direction and orientation  (1-2)Lowest administrative units. Localities  (1-5)Dependent or semi-dependent territories  (1-6)States or groupings of states from various points of view  (1-7)Places and areas according to privacy, publicness and other special features  (1-8)Location. Source. Transit. Destination  (1-9)Regionalization according to specialized points of view  (100)Universal as to place. International. All countries in general  (2)Physiographic designation  (20)Ecosphere  (21)Surface of the Earth in general. Land areas in particular. Natural zones and regions  (23)Above sea level. Surface relief. Above ground generally. Mountains  (24)Below sea level. Underground. Subterranean  (25)Natural flat ground (at, above or below sea level). The ground in its natural condition, cultivated or inhabited  (26)Oceans, seas and interconnections  (28)Inland waters  (29)The world according to physiographic features  (3)Places of the ancient and mediaeval world  (31)Ancient China and Japan  (32)Ancient Egypt  (33)Ancient Roman Province of Judaea. The Holy Land. Region of the Israelites  (34)Ancient India  (35)Medo-Persia  (36)Regions of the so-called barbarians  (37)Italia. Ancient Rome and Italy  (38)Ancient Greece  (39)   Catalan regions  (399)Other regions. Ancient geographical divisions other than those of classical antiquity  (4/9)Countries and places of the modern world  (4)Europe  (5)Asia  (6)Africa  (7)North and Central America  (8)South America  (9)States and regions of the South Pacific and Australia. Arctic. Antarctic 

(=...) Common auxiliaries of human ancestry, ethnic grouping and nationality. Table 1f

They are derived mainly from the common auxiliaries of language =... (Table 1c) and so may also usefully distinguish linguistic-cultural groups, e.g. =111 English is used to represent (=111) English speaking peoples

 (=01)Human ancestry groups  (=011)European Continental Ancestry Group  (=012)Asian Continental Ancestry Group  (=013)African Continental Ancestry Group  (=014)Oceanic Ancestry Group  (=017)American Native Continental Ancestry Group  (=1/=8)Linguistic-cultural groups, ethnic groups, peoples [derived from Table 1c]  (=1:1/9)Peoples associated with particular places                e.g. (=111:71) Anglophone population of Canada 

"..." Common auxiliaries of time. Table 1g

 "0/2"Dates and ranges of time (CE or AD) in conventional Christian (Gregorian) reckoning  "0"First millennium CE  "1"Second millennium CE  "2"Third millennium CE  "3/7"Time divisions other than dates in Christian (Gregorian) reckoning  "3"Conventional time divisions and subdivisions: numbered, named, etc.  "4"Duration. Time-span. Period. Term. Ages and age-groups  "5"Periodicity. Frequency. Recurrence at specified intervals.  "6"Geological, archaeological and cultural time divisions  "61/62" Geological time division  "63"Archaeological, prehistoric, protohistoric periods and ages  "67/69" Time reckonings: universal, secular, non-Christian religious  "67"Universal time reckoning. Before Present  "68"Secular time reckonings other than universal and the Christian (Gregorian) calendar  "69"Dates and time units in non-Christian (non-Gregorian) religious time reckonings  "7"Phenomena in time. Phenomenology of time 

-0 Common auxiliaries of general characteristics. Table 1k

 -02Common auxiliaries of properties  -021Properties of existence  -022Properties of magnitude, degree, quantity, number, temporal values, dimension, size  -023Properties of shape  -024Properties of structure. Properties of position  -025Properties of arrangement  -026Properties of action and movement  -027Operational properties  -028Properties of style and presentation  -029Properties derived from other main classes  -03 Common auxiliaries of materials  -032Naturally occurring mineral materials  -033Manufactured mineral-based materials  -034Metals  -035Materials of mainly organic origin  -036Macromolecular materials. Rubbers and plastics  -037Textiles. Fibres. Yarns. Fabrics. Cloth  -039Other materials  -04 Common auxiliaries of relations, processes and operations  -042Phase relations  -043General processes  -043.8/.9 Processes of existence  -045Processes related to position, arrangement, movement, physical properties, states of matter  -047/-049General operations and activities  -05 Common auxiliaries of persons and personal characteristics  -051Persons as agents, doers, practitioners (studying, making, serving etc.)  -052Persons as targets, clients, users (studied, served etc.)  -053Persons according to age or age-groups  -054Persons according to ethnic characteristics, nationality, citizenship etc.  -055Persons according to gender and kinship  -056Persons according to constitution, health, disposition, hereditary or other traits  -057Persons according to occupation, work, livelihood, education  -058Persons according to social class, civil status 

Special classifications based on or used in combination with UDC

• Universal Decimal Classification for Use in Polar Libraries - Scott Polar Research Institute, Cambridge
• BBC LonClass
• Global Forest Decimal Classification

Other faceted classifications:

• Bliss bibliographic classification
• Colon classification
• Broad System of Ordering

Other library classifications

• Dewey Decimal Classification
• Library of Congress Classification
• Russian Library-Bibliographical Classification (BBK)
• Chinese Library Classification
• Harvard-Yenching Classification