All tutorials and examples of how to cabalize a Haskell package assume that the package has one author (as well as one maintainer). How to properly assign multiple authors in a .cabal file?
I don't know if this is best practice, but I just use a comma-separated list of names.
Author: John Doe, Tikhon Jelvis
You can also provide email addresses:
Author: John Doe <john.doe@example.com>, Tikhon Jelvis <tikhon@berkeley.edu>