List all authors the first time you cite the source. in subsequent citations, only use the first author's last name followed by "et at." for example. first , cornell, sun, berry,

It is the APA style format to cite more than one author subsequently

Explanation:According to the question if first time citatations for multiple authors are to be listed then for the first time we simply list down the first names of all the authors,while for subsequent or the repeatedly the same are to be listed we simply have to write the last name of first author in the list and the rest are represented with "et at."

EXAMPLE 1:1st time citation : something written by Kernis,Cornell,Sun,Berry and Harlow have written something in 1993 would be cited like >

(Kernis, Cornell, Sun, Berry, & Harlow, 1993)

EXAMPLE 2: The second or third and so on times if the same reference is to be cited again or repeatedly, then it would be ===>

(Kernes et al. 1993)

OR

APA also allows to List all the authors first name as in example 1, EVERY time we cite the same references

Example 3(same as example 1)

(Kernis, Cornell, Sun, Berry, & Harlow, 1993)

i think it is the third one.