Do I have to cite the source of my notes based off of a deceased professor's notes, Let's say I'm writing a set of notes on a specialized topic, based off of notes from a deceased professor, who he himself had a disclaimer that his notes (theorems, proofs, ideas) were not properly attributed and cited, due to time constraints.  What should I do then, if I plan to distribute my notes / post it on a website?  Should I have a disclaimer of my own?
Ideally,you should track down the original sources for the theorems. However, I realise that might not be practically feasible due to eg time constraints, so providing your own disclaimer and citing the other professor's notes should be sufficient.