Follow APA's author/date system when crediting information contained in the text of your paper to a source, according to the Purdue University Online Writing Lab (OWL). See the example below.
Jones (1999) found that...
(Jones, 1999).
Use the word "and" when citing two authors' names in text. Use an ampersand with three or more names, or when the names are contained in parentheses.
Jones and Johnson (1954) discovered...
(Jones & Johnson, 1954).
List all authors for works with three to five authors the first time you cite a source in either style. Include only the first author's name followed by "et al." in all subsequent citations, as shown below.
(Johnson, Jones, Martinez, & Samuels, 2002).
(Johnson, et al., 2002).
Use only the first author's name for works with six or more authors.
Johnson, et al. (2009) claim...
(Johnson, et al., 2009).
Cite multiple sources in the order they appear in your reference list as follows.
(Johnson, 2002; Martinez, 2008; Zack, 2007).
Follow the author/date system in your reference list as well. Purdue's OWL advises that the following rules apply to all types of sources included in the reference list including books, journals and electronic sources.
List the author's last name followed by the author's initials and the date of the work in parentheses.
Jones, R. T. (2002).
Separate the names of two authors using an ampersand.
Jones, R. T., & Martinez, J. R. (1994).
List the names of three to seven authors using a comma to separate each name, except for the last name, which is preceded by an ampersand.
Jones, R. T., Martinez, J. R., Martinez, R. P., Samuels, C., & Modano, E. L. (1993).
For sources with more than seven authors, follow this example from Purdue's OWL:
Miller, F. H., Choi, M. J., Angeli, L. L., Harland, A. A., Stamos, J. A., Thomas, S. T., . . . Rubin, L. H. (2009).
Follow the format below, which shows a complete citation, for sources from periodicals, such as academic journals.
Author, A. A., Author, B. B., & Author, C. C. (Year). Title of article. Title of periodical, volume number(issue number), page(s).
Follow the format below to cite books in your reference list.
Author, A. A. (Year of publication). Title of work: Capital letter also for subtitle. Location: Publisher.