Purdue OWL - APA Formatting and Style GuideAPA (American Psychological Association) style is most commonly used to cite sources within the social sciences. This resource, revised according to the 6th edition, second printing of the APA manual, offers examples for the general format of APA research papers, in-text citations, endnotes/footnotes, and the reference page. For more information, please consult the Publication Manual of the American Psychological Association, (6th ed., 2nd printing).