Psychology: Quick Start Guide: Cite Your Sources (APA Style)

APA basics and style sheets from GSU Library's citation guide

Use for citing books, encyclopedia articles, and items from print copies of magazines and journals.

Use for citing articles and other resources from GALILEO databases.
Note: If you access articles through the GSU homepage, you can leave out the part that says, "Available through GALILEO." Some instructors want you to include the doi, like this:
Goldstein, G., Luther, J. F., Jacoby, A. M., Haas, G. L., & Gordon, A. J. (2008). A preliminary classification system for homeless veterans with mental illness. Psychological Services, 5, 36-48. doi:10.1037/1541-1559.5.1.36

Use for citing information from web sites, blogs, wikis, audio CDs, DVDs, etc.

These tutorials created by the American Psychology Association explains the basics of APA style.

From the Online Writing Lab (OWL) at Purdue University.