APA recommends an author-date system of citations that combine signal phrases and parenthetical references in the text of a paper (in-text citations) with a list of references at the end of the paper.

The guidelines presented here are consistent with advice given in the Publication Manual of the American Psychological Association, 6th ed. (2010).

How to use citations in the text of your paper (in-text citations)

A signal phrase indicates that something taken from a source (a quotation, summary, paraphrase, or fact) is about to be used. Usually, the source is introduced by a signal phrase that includes the last name(s) of the author(s) followed by the year of publication in parentheses.

The material being cited is followed by a page number in parentheses (unless the source does not have page numbers, as is often the case with Web sources).

As researchers Yanovski and Yanovski (2002) have explained, obesity was once considered “either a moral failing or evidence of underlying psychopathology” (p. 592).

How to list references at the end of your paper (reference list)

At the end of the paper, an alphabetized list of references gives complete publication information about all the references the writer cites in the text of the paper. The list is arranged alphabetically by authors’ last names.

Yanovski, S. Z., & Yanovski, J. A. (2002). Drug therapy: Obesity. The New England Journal of Medicine, 346, 591-602.