APA Style. This handout is based on the 6th edition of the Publication Manual of the American Psychological Association (APA), but is not a comprehensive guide. Writing in American Psychological Association Style. A Descriptive and Illustrative Sample. I. M. Author. Location of Professional Affiliation. Abstract The American Psychological Association (APA) is a scientific and professional organization that represents psychologists in the United States. APA educates the public. Please use the example at the bottom of this page to cite the Purdue OWL in APA. To see a side-by-side comparison of the three most widely used citation styles.