6-digit UNESCO nomenclature
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. External links. The article covering the full 6-digit nomenclature is incomplete in this English-language edition of Wikipedia but may be found in the Spanish-language edition at .