Most of the major style guides can be found at Pace University's Campus Libraries. Information you need to locate the books (call numbers and locations) can be found here. Ask at the circulation or reference desk if you're having trouble finding a book.
There are many different citation styles, but most students need to learn to follow the conventions of only MLA or APA. Style guides are about more than just citing sources of information or ideas. Guides can help you improve the style of your writing, for example.
Any citation you provide should enable your reader to find that source. Make sure your citation gives the reader the information he or she needs to find the source you used.
It's a good idea to purchase a copy of the style guide that your major or graduate program follows: MLA for the humanities and APA for the social sciences.
The Excelsior Online Writing Lab offers excellent instruction regarding various style guides. In the past, Purdue University's Online Writing Lab (OWL) Guide was very popular and useful. However, due to changes to the structure and content of OWL that resulted from partnership with a for-profit company, I have decided to stop recommending Purdue Owl.