APA (7th ed.) Citation

Deller, A., & Deller, M. (1968). Duets for countertenors. Vanguard Cardinal Series.

Chicago Style (17th ed.) Citation

Deller, Alfred, and Mark Deller. Duets for Countertenors. Vanguard Cardinal Series, 1968.

MLA (9th ed.) Citation

Deller, Alfred, and Mark Deller. Duets for Countertenors. Vanguard Cardinal Series, 1968.

Warning: These citations may not always be 100% accurate.