APA, MLA, Chicago...What style manual is your class using?
The Purdue Online Writing Lab (OWL) has over 200 free resources including ■Writing and Teaching Writing ■Research ■Grammar and Mechanics ■Style Guides ■ESL (English as a Second Language) ■Job Search and Professional Writing.
OWL also has detailed instructions on;
MLA citations; APA citations; Chicago Manual of Style citations
Interactive site that helps to format your paper in the required citation style.