APA (7th ed.) Citation

Gershwin, G., Porter, C., Rodgers, R., & Walters, R. (1992). Popular ballads for classical singers: Low voice. Hal Leonard.

Chicago Style (17th ed.) Citation

Gershwin, George, Cole Porter, Richard Rodgers, and Richard Walters. Popular Ballads for Classical Singers: Low Voice. Milwaukee: Hal Leonard, 1992.

MLA (9th ed.) Citation

Gershwin, George, et al. Popular Ballads for Classical Singers: Low Voice. Hal Leonard, 1992.