AGRICOLA -- Guide to Subject Indexing

Such a hierarchy is clearly not desirable, but as long as it exists, an indexer may use thedescriptor KEYS in the sense of either a tool for opening a door or a dichotomous keyfor identifying an organism. It is our understanding that many of these mixedhierarchies will be eliminated from the second edition of the Thesaurus.A USED FOR reference is not limiting in the same way that a hierarchy is.• E.g., MYCOSESo uf dermatomycoseso uf histoplasmosisThis is not to be construed as restricting the use of the descriptor MYCOSES to thesetwo particular mycoses. In other words, "uf" means "used for"; it does not mean "usedexclusively for".No. 8, October 1986SUBJECT: First descriptorIn response to Sarah Thomas's memo of September 19, 1985, NAL indexing policy hasbeen to assign, if possible, as the first descriptor one which is compatible with AGRIS'srequirements for a primary descriptor. The question has arisen whether it is necessary toisolate a commodity, animal, etc., as the first descriptor if the name of the commodity,animal, etc., appears as the first word of a precoordinated (multi-word) descriptor. Theanswer is that it is not necessary to do so solely to comply with this policy.• E.g., An article on milk yield can be indexed with MILK YIELD as the firstdescriptor. It is not necessary to use in field 650: milk; milk yield. An article oncattle diseases can be indexed with CATTLE DISEASES as the first descriptor.It is not necessary to use in field 650: cattle; cattle diseases.It is, of course, necessary to use MILK in addition to MILK YIELD or CATTLE inaddition to CATTLE DISEASES if the subject content of the article warrants the useof both. In that case, enter MILK or CATTLE as the first descriptor.No. 9, November 198624