plate creates a list of contributors for citations based on the "primary" contributors in the publication. It reverses the first name, adds "et al" as needed when the contributors list is beyond a certain length, handles adding ed(s)/editor(s) as called for. It returns the list without end punctuation, so should be followed by a period.

See https://www.chicagomanualofstyle.org/book/ed17/part3/ch14/psec076.html for rules on the inclusion of contributors.
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