During the final confrontation between Batman and The Joker, The Joker asks Batman who he really is beneath his mask. When hazarding a guess The Joker mentions the names of 2 other Batman characters, Harvey Dent (Two Face)featured in Chris Nolan's 'The Dark Knight' and Carl Grisham, a character from the 1989 Tim Burton classic, 'Batman'.
The film works as something of an homage to former Batman incantations, which is clear in the soundtrack with both Danny Elfman's and Hans Zimmer's Batman motion picture soundtracks being featured.