Here are entered general works describing the resources and collections available in libraries for research. Works describing library resources and collections available in a particular field are entered under the subject with subdivision Library resources, e.g. Biology--Library resources; United States--Library resources.
Here are entered works on the periodicals of the world and, with appropriate subdivisions, works on special aspects or sections of periodicals. Works on periodicals in a specific language, or in a specific country or larger area, are entered under the adjectival form of the language or area, e.g. Arabic periodicals; Canadian periodicals. --subdivision Periodicals under specific subjects, e.g. Engineering--Periodicals; United States--History--Periodicals