Two to seven authors: List by their last names and initials, separated by a comma. Put an & between the final two names.
Brooks, K., & Dunn, R.
Knowles-Carter, B., Carter, B.I., & Carter, S.
More than seven authors: List by last names and initials; commas separate author names. After the sixth author's name, use an ellipses in place of the author names. Then provide the final author name. There should be no more than seven names.
Ehrlich, H., Shaala, L. A., Youssef, D. T., Żółtowska-Aksamitowska, S., Tsurkan, M., Galli, R., ... & Ivanenko, V. N. (2018). Discovery of chitin in skeletons of non-verongiid Red Sea demosponges. PloS One, 13(5), e0195803.
Name both authors in the signal phrase or in the parentheses. Use and between the authors' names within the text and use the & in the parentheses. Don't forget the year of publication and page numbers (if there are any).
(Bricco & Chapman, 2016, p.52)
(Schilcher & LaPlante, 1997)
Research by Schilcher and LaPlante (1997) shows...
Three to five authors:
List all the authors in the signal phrase or in parentheses the first time you cite the source. Use the word and between the authors' names within the text and use the & in the parentheses. Don't forget the year of publication and page numbers (if there are any).
In subsequent citations, only use the first author's last name followed by "et al."