When in doubt about citations, ask the O.W.L. Photo courtesy of Phil Reed
One of the most reliable online resources for MLA, APA, and Chicago style citations is The Purdue Online Writing Lab (affectionately dubbed "The O.W.L."), where you will find detailed style guides for all three of these styles, along with American Medical Association Style.
The library also has an online guide that provides guidance in the major citation styles. We also have paper copies of the major style guides shelved right near the reference desk.
Citing archival material, such as a primary source letter or another print document, is different than citing other library material such as books, journals, or articles. See the library's guide to archival citations for information on how to cite archival material in APA, MLA, and Chicago Style.
There are at least three reasons why writers cite their sources:
When you are preparing a document,use this checklist to be sure your citaitons are complete.
Because scholars in different disciplines emphasize different things when they read citations, there are many different styles. The MLA style, used for literary studies, makes sure page numbers are provided in an in-text citaiton because the exactness of a quotation matters; the APA style used in psychology and other social sciences include the year of publication, because when research was conducted is considered particularly significant. The Chicago Style is used by disciplines such as history and religion, which value sources so much it's common to put all the information about a source in a footnote as well as in a bibliography at the end of a paper.
Whatever style you use, citations typically include author, title of the work, and publication informaiton (for books, place, publisher, and year published; for articles, the journal, volume, date, and page numbers; for websites, a URL may be needed).