Cita APA (7th ed.)

Dent, E. J. (1940). Ópera. Penguin Books.

Cita Chicago (17th ed.)

Dent, Edward J. Ópera. Harmondsworth: Penguin Books, 1940.

Cita MLA (9th ed.)

Dent, Edward J. Ópera. Penguin Books, 1940.