Publication Manual of the American Psychological Association (6th ed.)
This is the definitive source! All other APA guides (print or electronic) are based on this manual!
BF 76.7 .P83 2010 REF
Library's Revised APA Handout (6th ed.)
http://www.ubishops.ca/library_info/pdf/APAguide6thedofficial2010.pdf