Brown & Rushton 2001, Introduction and "1. Ancestry, early life and training."; Heartz 1988, pp. 517–526. Sources differ concerning Gluck's nationality: Kuhn 2000, p. 272, and Croll 1991, p. 308, said he was German, while Brown & Rushton 2001 and Howard 2003 (p. xi) gave Bohemian; Hayes et al. 1992, p. 453, Bohemian-Austrian; and Harewood & Peattie 1997, p. 261, Austrian; G. Banat, p. 144 recognized him as Bavarian.