UNESCO Nomenclature (more properly UNESCO nomenclature for fields of science and technology) is a system developed by UNESCO for classification of research papers and doctoral dissertations. There are three versions of the system, offering different levels of refinement through 2-, 4-, and 6-digit codes.
The following links do not link directly to topics. Instead, they link to pages on which the 6-digit UNESCO nomenclature is described in more detail: it is far too large a system to cover on a single page.
11 Logic
12 Mathematics
21 Astronomy, Astrophysics
22 Physics
23 Chemistry
24 Life Sciences
25 Earth and space science
31 Agricultural Sciences
32 Medical Sciences
33 Technological Sciences
51 Anthropology
52 Demography
53 Economic Sciences
54 Geography
55 History
56 Juridical Science and Law
57 Linguistics
58 Pedagogy
59 Political Science
61 Psychology
62 Sciences of Arts and Letters
63 Sociology
71 Ethics
72 Philosophy
While as of October 2004[update] the English-language Wikipedia lacks articles on the specific 6-digit categories, they are all available in Spanish, linked from es:Clasificación Unesco 6 dígitos.
There is also available the original UNESCO "PROPOSED INTERNATIONAL STANDARD NOMENCLATURE FOR FIELDS OF SCIENCE AND TECHNOLOGY", from 1988, at UNESCO Archives, describing the nomenclature system.