There are multiple citation styles. The three most commonly used citation styles are APA, MLA and Chicago. Talk to your professor to determine the appropriate citation format before you start your research paper.
Style manuals provide guidance and examples of how to write and cite in a particular style.
Publication Manual of the American Psychological Association by 
MLA Handbook by You can find many websites that provide help with citation styles but not all are accurate or up to date. Here are some of best websites to find citation help.
