Cerebus Archive No. 10 "Ali Baba, Prince of Thieves". Remember back in issue #6 when Dave Sim said that he only had a few tiny reproductions of his original layouts for "Ali Baba"? Turns out he was wrong.
How the 1976 story ended up in the June, 1980 section of the Cerebus Archive and how "Ali Baba" was very much an immediate precursor of Cerebus is covered in this issue.