Gaya APA

Horacek, L., Lefkoff, G. (1989). Programmed ear training : volume 1 intervals, melody and rhythm (2nd ed). Florida: Harcourt Brace Jovanovich.

Gaya MLA

Horacek, Leo., Lefkoff, Gerald. "Programmed ear training : volume 1 intervals, melody and rhythm". 2nd ed Florida: Harcourt Brace Jovanovich, 1989. Text.