b'The Grammar of Subject Headings / Subdivisionsadvantage of subdivisions over phrase headings for complex subjects is that uniformity can be morereadily achieved with subdivisions. Once the subdivisions have been established, they can beappended to any applicable subject heading without guessing or straining the language for a suitablephrase. Subject strings with topical subdivisions can be read backwards: Clothing and dress History, for example, means the history of clothing and dress, and OceanographyResearch Ethical aspects means ethical aspects of research in the field of oceanography.Geographic SubdivisionsAnother aspect of subjects that can be brought out in subdivisions is geographic specificity. The unitused as a subdivision may be the name of a country, state, city, or other geographic area. A topicalheading with a geographic subdivision means simply that topic in a particular place. Bridges France, for example, is the appropriate subject string for a work on bridges in France, andAgricultureOhio for a work on agriculture in Ohio.There are only two types of topical subject headings that can never be subdivided geographically.The first are those headings, such as Exploration or Church history, that are used instead assubdivisions under geographic headings, as in Arctic regionsExploration or United States Church history.The second are those subjects, mostly in the fields of literature and the arts, for which thegeographic qualification is conveyed by a modifying adjective rather than by a subdivision. Many ofthese subjects have a general reference similar to this reference at the subject Authors: SA[Seealso] authors of particular countries or regions, e.g. American authors.Beyond these two types of headings that are never subdivided geographically there is a broadspectrum. Not all other topical headings lend themselves logically or practically to geographicsubdivision. Some topics, such as Fractions or Femininity of God, are either nonphysical or tooabstract to have a geographic location. Others are physical but not easily located in a particularplace, such as Computer viruses or Space debris. Still other headings, such as Pet therapy orLung cancer, are unlikely to be dealt with geographically, at least in works that would be found in asmall library.Many subject headings in the Sears List are followed by the parenthetical phrase (May subdiv.geog.). In application this means that if the work in hand deals with that subject in general, only theheading itself is used; but if it deals with the subject in a particular place, the heading may besubdivided geographically. If, however, a library feels the need to subdivide any subject headinggeographically that is not so indicated in the List, the library should do so without hesitating,provided, of course, that the heading does not fall into one of the two types of headings that cannever be subdivided geographically.Headings with a geographic adjective may sometimes be further subdivided geographically. Theadjective then denotes the place of origin while the subdivision represents the location where theA-29'