ABSTRACT
Bibliographic sources are as diverse as the fields they cover. The majority of the works listed later in this guide are bibliographic sources of one sort or another. Many are published as books. Bibliographic sources are not created equal. They vary from each other along several important dimensions. The amount of information provided in each entry is probably the most obvious measure of a bibliographic source. An abstract is more detailed than an annotation and thus typically more useful. In one or two paragraphs, an abstract summarizes or condenses the work. Some bibliographic sources are devoted exclusively to certain forms of publications, such as, The Monthly Catalog of Government Publications, or Dissertation Abstracts International, for instance. Every bibliography has a cut-off date. Bibliographic sources also differ in their arrangement of references. The linguistic factor is of utmost importance, especially in sources organized by subject.
