The American Psychological Association (APA) has more than 122,500 members. It was founded by 31 members in 1892. The APA publishes over 90 journals as well as special issues from these journals.
If you are a member of the APA or a student in one of the many branches of psychology or in many of the other social sciences and education, you will need to use APA style in your papers. One of the best online tools for the APA style is at the Purdue Online Writing Lab. It can be found at: https://owl.english.purdue.edu/owl/section/2/10/ Here is a Quick Citation Guide from Penn State: https://www.libraries.psu.edu/psul/researchguides/citationstyles/APA_citation.html#online-electronic