Choose the most specific subject identifier available. Do not add broader or narrower or related subject identifiers. Instead, allow the syndetic structure to provide this kind of access. Choose the most co-extensive subject identifier available. If there is no single co-extensive subject identifier available, add the number of subject identifiers necessary to summarize the overall subject matter of the work. Do not index the work by adding subject identifiers for the subject matter covered by a chapter or other portion of the work. Use the syndetic structure to provide this kind of access instead.
18.104.22.168 Specificity and co-extensivity