Citing Sources APA Style

APA Style -- Purdue University Library
http://owl.english.purdue.edu/owl/resource/560/01/

APA Style Guidance and Tutorials from APA
http://www.apastyle.org/learn/index.aspx

APA Style Guidance from Vanguard University
http://www.vanguard.edu/faculty/ddegelman/index.aspx?doc_id=796