I have been researching on finding optimal solutions to generating University Time Table using Genetic Algorithm. I am searching for a Academic Paper, that properly defines the University Time Table design problem and proves it is NPC.
Simple Google search reveals a thesis from 2010 that defines and proves the complexity of scheduling university courses as NP-Complete. See Fig. 42 towards the end.
Lovelace, April L. "On the complexity of scheduling university courses." (2010).
There is also a technical report dating back to 1995 that does the same thing:
Cooper, Tim B., and Jeffrey H. Kingston. The complexity of timetable construction problems. Springer Berlin Heidelberg, 1996.