APA (7th ed.) Citation

Gershwin, G., Gershwin, I., & Heyward, D. (1935). Porgy and Bess: [an American folk opera]. Gershwin.

Chicago Style (17th ed.) Citation

Gershwin, George, Ira Gershwin, and DuBose Heyward. Porgy and Bess: [an American Folk Opera]. New York: Gershwin, 1935.

MLA (8th ed.) Citation

Gershwin, George, et al. Porgy and Bess: [an American Folk Opera]. Gershwin, 1935.

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