In the Reference List
Separate the names with a comma and an ampersand if there are two authors. For example, "Jones, A. W., & Smith, J."
Use commas between the names for three to seven authors and include an ampersand between the last two names. For example, "Jones, A. W., Smith, J., White, E. E., & Black, T."
List the first six names, then three ellipses, then the last name if there are eight or more authors. Include a comma after the sixth name, but use neither a comma nor an ampersand after the ellipses. For example, "Jones, A. W., Smith, J., White, E. E., Black, T., Fort, W., Aaron, P. B., . . . Brown, K."
In In-text Citations
Use an ampersand between the names of two authors in a parenthetical citation; for example, "(Jones & Smith, 2010)." Use the word "and" if you list the authors in the text. For example, "According to Jones and Smith (2010)."
List all the authors' names the first time you cite a reference with three to five authors. For example, "(Jones, Smith, & White, 2010)" or "According to Jones, Smith, and White (2010)." Include only the first author's name followed by "et al." for subsequent citations of the same reference: "(Jones et al., 2010)" or "According to Jones et al. (2010)."
Use the first author's name and "et al." for every citation of references with six or more authors. For example, "(Smith et al., 2010)" or "According to Smith et al. (2010)."