APA style provides a format to cite theories and other information in a specific way so anyone reading your work knows what is not original. This includes research or theories that both support and disagree with your hypothesis. APA style requires that you both write an in-text parenthetical citation and a note in a reference list when referencing a person's theory. Even if you write a person's theory in your own words without a direct quote, called paraphrasing, you still have to cite the author.
In-text citations are a note within the text that credits referenced material. In-text citations are similar to footnotes, but they are placed within sentences instead of at the bottom of pages. When paraphrasing an author's theory, place the publication year of the referenced material in parentheses following the author's name in the sentence. If you quote an author, include the author's last name, a comma, the publication year, a comma and page number after a "p." all in parentheses at the end of the quote. For two authors, add an "&" between last names and omit the page number.
The reference list tells readers specifically what the sources are that you referenced in your in-text citations. The reference list is at the end of the paper. Use double-spacing and a hanging indent paragraph style. Begin an entry with the author's name or names, the publication year, the title of the referenced material and the publication data. Publication data includes article titles, volume numbers and page numbers. Write the author's last name and first initial. Use commas and an "&" for multiple authors. Place the year in parenthesis. Italicize the publication data and separate page numbers with an em dash.
Although most citations in APA style follow a basic pattern, there are several exceptions that cannot be accounted for in a basic guide. Use of online references, personal communications and unpublished manuscripts are just some examples of materials that may require a format modification. Also, APA manual is updated annually. For the most current rules regarding APA style, consult the latest edition of the style guide. Keep in mind that professors sometimes have their own preferences when using APA style. They may prefer older methods for citation or require students to make citations differently from APA style in some instances.