[FOM] Truth definitions

[T.Forster@dpmms.cam.ac.uk]

   I promised one of my Ph.D. students that i would write out a tutorial on 
truth-definitions for him.  One example it would be nice to work through is 
a consistency proof of ZF in the impredicative class theory commonly known
as Morse-Kelley.  It occurs to me that an idea that good must have been had 
before, and that there must be an elementary treatment in the literature 
somewhere.  Can listmembers point me at one?

                  tf