Gaya APA
Lefkoff, L, H, G. (1989).
Programmed Ear Training : 2st : Vol. II (2).
San Diego:
Harcourt Brace Jovanovich.
Gaya MLA
Lefkoff, Leo, Horacek,, Gerald.
"Programmed Ear Training : 2st : Vol. II".
2
San Diego:
Harcourt Brace Jovanovich,
1989.
Text.