What is an APA style?

APA format is the official style of the American Psychological Association (APA) and is commonly used to cite sources in psychology, education, and the social sciences. APA format originated in a 1929 article published in Psychological Bulletin that laid out the basic guidelines. These guidelines were eventually expanded into the APA Publication Manual.

Writing References Sample:

sources:
http://psychology.about.com/od/apastyle/a/apageneral.htm
http://psychology.about.com/od/apastyle/ig/APA-Format-Examples/