Section 8.17 of the APA Manual, 7th edition, provides details on the number of authors to be included in in-text citations. As per this section, any work having 3 or more authors will not be written fully. Instead, the Latin words “et al” meaning “and others” have to be used after writing the first author’s name.
Example In-Text Citation Entry for more than 3 authors:
Almost all suppressed persons end up becoming an oppressed person when the same set of situations is presented in their lives (Camus et al., 1975).
In a rare instance, multiple sets of three or more authors might have the same initial pair or initial author. Under such rare situations, Section 8.18 of the APA manual requires you to write out the names of authors in order to distinguish between such confusing references.
Example In-Text Citation Entries:
Bandopadhyay, Schmidt, Wagner et al. (2000)
Bandopadhyay, Schmidt, Meyer et al. (1975)