Found this study, by Frantisef Josef Prokop, Third Prize Moscow international tournament, 1925. White to play and draw. It's pretty neat, but I dont understand why white does not just promote to Queen on move 1?
Maybe it was because it would have handed the tempo to black(allowing him to begin to check/fork whit's king and black didn't want to allow that) Maybe it was just a blunder? I don't know.
f8=Q, loses the knight. After black trades the white bishop with any other piece then checkmate is inevitable. B+N (or B+B checkmate if white takes pawn with bishop). I believe some responses above already address this.