Obama was NOT ever a constitutional law professor. He was a lecturer that was put in that position as a means of providing him with a living stipend while he was being groomed.
The only public picture of him in this capacity shows him in front of a blackboard (is that racist) with a bunch of community activist organizing nonesene on it. The cannard that he was a "professor" keeps getting repeated even by commentators that should know better.
I suppose the employment records of the University of Chicago have gone the way of his transcripts, passport records, Selective Service records, Social Security records, birth records, parents’ marriage and divorce records, etc.