APA (7th ed.) Citation

Apel, W. (1944). The notation of polyphonic music, 900-1600 (2d, corr. ed.). The Mediaeval Academy of America.

Chicago Style (17th ed.) Citation

Apel, Willi. The Notation of Polyphonic Music, 900-1600. 2d, corr. ed. Cambridge, Mass.: The Mediaeval Academy of America, 1944.

MLA (9th ed.) Citation

Apel, Willi. The Notation of Polyphonic Music, 900-1600. 2d, corr. ed. The Mediaeval Academy of America, 1944.