Here is information of two main citation styles that you can use for the reference lists/bibliographies of your papers.
APA Style Guide (Purdue) - From the American Psychological Association. Often preferred in the fields of psychology and many other social sciences.
MLA Style Guide (Purdue) - From the Modern Language Association of America. Often preferred in the fields of literature, arts, humanities, and in some other disciplines.
Where do I find the most authoritative information about these styles?
If you have questions or citations not covered by the guides linked to here, consult one of the following official style manuals. If you consult other, less official manuals or online style guides that purport to explain these style, please be aware that these sometimes contain errors which conflict with the official guides or may refer to earlier editions.
Publication Manual of the American Psychological Association. 6th ed. Washington, DC: American Psychological Association, 2010 (call number: BF76.7.P83 2010, multiple libraries). Official APA style guide.
MLA Handbook for Writers of Research Papers. 7th ed. New York: Modern Language Association of America, 2009 (call number: LB2369.G53 2009, multiple libraries). A somewhat simplified guide, adequate for undergraduate and most other research papers.