Citation format for citing sources in your papers.
Style guide for formatting text, headings, title page, etc.
Published in the Publication Manual of the American Psychological Association, 7th Edition.
APA requires you to use DOIs (Digital Object Identifiers -- individual numbers given to individual journal articles) in your citation to any journal article that has one. Stephanie Wiegand of the University of Norther Colorado Library has a page on journal articles ishere, and her page on DOIs is here (for further examples).
There are several copies (old and new) at the library. Please search in QuickFind for updated call numbers, or come to the Help Desk for assistance in locating a copy.
The Help Desk at the library also has a condensed APA style guide handout that you can request (photocopy handout).