No single index can be used to locate articles from all periodicals. Each index uses a different set of periodicals, and it is the nature of the group of periodicals that determines the subject approach of the index. Some indexes, such as Expanded Academic Index , use as their basis a wide variety of subject areas. Expanded Academic Index includes in its database records for articles from periodicals that are the most widely held in college and university libraries regardless of subject. Other indexing services, such as PsycINFO , will only include articles from scholarly journals in specialized fields.
Indexes often overlap their coverage.
Some periodicals may be indexed in several different sources, but no one index is comprehensive enough to be the only source you need to consult in your research. Format Indexes take many forms. They may be computer databases or paper products. Some publishers offer the same indexing information in several formats. The database is also available in some libraries on a CD-ROM, but Ithaca College Library does not subscribe to the service in that format.