Publication Manual of the American Psychological Association by 
APA Style Simplified: Writing in Psychology, Education, Nursing, and Sociology by 
MLA Handbook for Writers of Research Papers, 7th ed.
Turabian's A Manual for Writers of Research Papers, Theses and Dissertations, 7th ed. by 
The ACS Style Guide by 
You may be plagiarising without realizing it. Plagiarism isn't only obvious theft such as buying a paper off the web or copying and pasting entire papers. Failing to properly cite the source of the words and ideas you use in your paper also constitutes plagiarism.
Plagiarism is theft of someone's words or ideas. "Plagiarism is pretending that an idea is yours when in fact you found it in a source. You can therefore be guilty of plagiarism even if you thoroughly rewrite the source's words. One of the goals of education is to help you work with and credit the ideas of others. When you use another's idea, whether from a book, a lecture, a Web page, a friend's paper, or any other source, and whether you quote the words or restate the idea in your own words, you must give that person credit with a citation." Harris, Robert A. Appendix. The Plagiarism Handbook: Strategies for Preventing, Detecting, and Dealing with Plagiarism. Pyrczak Publishing: Los Angeles, California, 2001. 132-133.
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