Chicago Sun-Times: M - Roger Ebert of the film "credited with forming two genres: the serial killer movie and the police procedural." - http://rogerebert.suntimes.com/apps/pbcs.dll/article?AID=/19970803/REVIEWS08/401010339/
M - Cast, crew, plot synopsis and review from the All Movie Guide. - http://www.allmovie.com/cg/avg.dll?p=avg&sql=A100745
Fritz Lang's M - Background information, storyline, political impact, history, pictures, and review. - http://www.cyberroach.com/m/
M (1931) - Full cast and crew for the film, and other information from the Internet Movie Database. - http://www.imdb.com/title/tt0022100/