A new research guide has been created and put online that addresses the proper format for citing sources in APA, MLA, and Chicago Style and can found here: http://library.gmu.edu/research/citationguide.pdf
Of course this guide is for quick reference and for a full explanation of each style, consult the manuals. We have several useful sources in the library’s reference collection, including these popular titles:
MLA style manual and guide to scholarly publishing / Joseph Gibaldi, PN147 .G444 1999
A pocket style manual : clarity, grammar, punctuation and mechanics, research, MLA, APA, Chicago, usage/grammatical terms / Diana Hacker, PE1408 .H26 2004
Publication manual of the American Psychological Association, BF76.7 .P83 2001
And for those studying business, we have The Gregg reference manual : a manual of style, grammar, usage, and formatting / William A. Sabin, PE1479.B87 S23 2005