Cita APA (7a ed.)

Whitney, N. (1996). Open Doors: Student´s Book. Oxford University Press.

Cita Chicago Style (17a ed.)

Whitney, Norman. Open Doors: Student´s Book. New York: Oxford University Press, 1996.

Cita MLA (9a ed.)

Whitney, Norman. Open Doors: Student´s Book. Oxford University Press, 1996.