The American Journal of Physical Anthropology style is 6 years out of date. It is similar to APA except for rules on et al. Specifically, articles with one or two authors include all names in every in-text citation; articles with three, four, or five authors include all names in the first in-text citation but are abbreviated to the first author name plus et al. upon subsequent citations; and articles with six or more authors are abbreviated to the first author name plus et al. for all in-text citations.