In the beginning the kids were told that John Lennon's killer was inspired by "A Catcher in the Rye". Later, when Butters was being interviewed on television the interviewer said that Ronald Reagan's attempted assassination was inspired by "A Catcher in the Rye".
In Stan's room there is a poster that reads, "The Street Warrior" with a character with leather attire. This is a reference to Mad Max 2: The Road Warrior (1981).