Pisarowitz 1970, p. 22 Contrary to the assumption of Heartz (1995, p. 277) and Fuchs (2009), Haydn did not stand godparent of Leutgeb's daughter (Lorenz 2013). Pisarowitz, Karl Maria (1970). "Mozarts Schnorrer Leutgeb; Dessen Primärbiographie". Mitteilungen der Internationalen Stiftung Mozarteum. VIII (3–4): 21–26. Heartz, Daniel (1995). Haydn, Mozart, and the Viennese School. Norton. Lorenz, Michael (2013). "A Little Leitgeb Research". michaelorenz.blogspot.co.at. Vienna.