↑ Butterworth 1978 [1977], p. 23: "In 1752 Haydn composed the music for a burlesque opera called Der Krumme Teufel (The Lame Devil)." [sic]
↑ Jurkowski, Henryk, with Francis, Penny, collab. ed. (1996). A History of European Puppetry: From Its Origins to the End of the 19th Century (Vol. 1 of A History of European Puppetry), Edwin Mellen Press, 427 pages, ISBN 0-7734-8803-0, p. 131: "[...], and others such as Der krumme Teufel (The Lame Devil), [...]"
↑ Barber, David W. (1990). When the Fat Lady Sings: Opera History as It Ought to Be Taught, Sound and Vision, 141 pages, ISBN 0-920151-11-6, p. 54: "Haydn wrote his first opera, Der krumme Teufel (The Crooked or Limping Devil) when he was just 19, and earning some extra money as a street musician in Vienna."
