Citation - A reference or footnote to a book, article, or other material that contains all the information necessary to identify and locate the work.
Abstract - A brief summary of the contents of a journal article or book.
Index - A printed or electronic publication which lists citations to journal articles or books.
Controlled Vocabulary - Assigned standardized terms used in searching a specific database or catalog. These terms will differ for each database. Sometimes called "subjects" or "descriptors."