We cite sources to acknowledge the work of others, as well as to avoid academic dishonesty, or plagiarism. There are various formats for citing sources and your instructior will tell you which to follow.
American Psychological Association or APA style is widely accepted in the Social Sciences. For more information consult the 6th edition on 2 North Reference and in Dictionary Stands on all floors: BF 76.7 P83 2010. Publication Manual sections are noted in square brackets [ ].