I did a post on the Grefe-Vukcevich game I witnessed at the US Championship in 1975 HERE.
Jeremy Silman relates how when he was a youngster, he met Grefe, then the new U.S. Champion, and asked Grefe, “Can I show you one of my games?” Grefe’s answer: “Where’s your money?” Funny thing, that’s the same thing Grefe asked a spectator at the US Championship in Oberlin 1975 when he asked Grefe, who was watching the post mortem, what he thought about the position. I also ran into Grefe on the streets of Chicago near one of the chess clubs. I forget which one it was, but he was there to play a match against one of Chicago’s leading players...Verber, maybe? Anyway, Grefe was dressed in an all white ‘guru suit’ that was filthy. You can read Silman’s article on Grefe on Chessdotcom HERE