The new Grove dictionary of opera

MLA

Grove, George, Christina Bashford, and Stanley Sadie. The New Grove Dictionary of Opera. London: Macmillan reference books, 1998.

APA

Grove, G., Bashford, C., & Sadie, S. (1998). The new Grove dictionary of opera. London: Macmillan reference books.

Chicago

Grove, George, The New Grove Dictionary of Opera. Edited by Christina Bashford and Stanley Sadie. London: Macmillan reference books, 1998.