The APA is the American Psychological Association. According to the APA website, the APA is "the largest scientific and professional organization representing psychology in the United States. APA is the world's largest association of psychologists, with more than 137,000 researchers, educators, clinicians, consultants and students as its members.
"The American Psychological Association has established a style that it uses in all of the books and journals that it publishes. Many others working in the social and behavioral sciences have adopted this style as their standard as well. ... You can find more information about APA Style at http://www.apastyle.org." from the APA website
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