The new Grove book of operas

MLA

Grove, George, and Stanley Sadie. The New Grove Book of Operas. London: Macmillan, 1996.

APA

Grove, G., & Sadie, S. (1996). The new Grove book of operas. London: Macmillan.

Chicago

Grove, George, The New Grove Book of Operas. Edited by Stanley Sadie. London: Macmillan, 1996.