If the article has three or more authors, list only the first author in the in-text citation, followed by "et al."
In the reference list, list up to six authors. If there are more than six authors, list only the first three in the reference list, followed by "et al."
See 13.23: Book with Multiple Authors or Editors, 13.107 Author-Date - Book with Multiple Authors.
In-text
(Hoffman et al. 2016, 600).
Reference list
Hoffman, Louis, Nathaniel Granger, Jr., Lisa Vallejos, and Michael Moats. 2016. "An Existential-Humanistic Perspective on Black Lives Matter and Contemporary Protest Movements." Journal of Humanistic Psychology 56 (6): 595-611. https://doi-org.ezproxy.library.ubc.ca/10.1177/0022167816652273.