After you have located an article or criticism in a periodical and have determined it to be useful for your paper, you should verify the credibility of the periodical.  A more credible title adds strength to an argument or position statement within a term paper.  For example, the National Enquirer and the American Literature: A Journal of Literary History, Criticism, and Bibliography are both periodicals; however, one is more appropriate than the other for assessing the writings of William Faulkner.  To help you decide which title is more appropriate (or credible) refer to Magazines for Libraries.

This particular source provides an annotated list and evaluations of some 6500 periodicals arranged by over 100 major subject headings.  Experts on each field or subject wrote the descriptions of each periodical.  Moreover, the annotations point out the strengths and weaknesses of each periodical in relation to similar titles.  After reading the comments about the National Enquirer and the American Literature:  A Journal of Literary History..., it should be clear which periodical would best evaluate Mr. Faulkner's writings.

To access the annotations, refer to the title and subject indexes located at the back of the volume. To find a critique of a given periodical, look up the periodical’s title in the “Title Index.”  In this index, all of the periodicals are listed alphabetically.  Find the title and write down the number that follows it.  This number indicates a paragraph in the main body of the book that evaluates this periodical.  Go to that paragraph and see if it specifies weather this periodical is a magazine, newspaper, newsletter, or journal.  There will be a short description of the kinds of articles found in this periodical.  The paragraph also describes the target audience and the type of library (if any) in which this periodical would be appropriate.  Using this information it is possible to determine if a periodical is a journal or magazine.  For example, if a periodical is described as appropriate for a research library it is more likely to be a journal or a well-respected magazine.     

The “Subject Index” works like the “Title Index;” however, you look up a topic or subject instead of a title. In this index, the numbers are listed below each subject.  Again, each number indicates a paragraph-long description of a periodical that is relevant to that specific subject.  Both indexes can be somewhat difficult to use, so don't hesitate to ask a librarian for help.