Fritz Haarmann: The Butcher of Hannover
Due to the unusual era and location of the crimes, there are consequently very few books with detailed information on Fritz Haarmann.
Bolitho, W. Murder for Profit (1926).
Lessing, T. Monsters of Weimar: Haarmann — The Story of a Werewolf (1993).
Marriner, B. A New Century of Sex Killers (1992).
Wilson, C. and D. World Famous Serial Killers (1992).