Cita APA (7a ed.)

Ward, A., & Whitney, N. (1995). Open doors: Teacher's book. 2.

Cita Chicago Style (17a ed.)

Ward, Ann, y Norman Whitney. Open Doors: Teacher's Book. 2. Oxford, 1995.

Cita MLA (9a ed.)

Ward, Ann, y Norman Whitney. Open Doors: Teacher's Book. 2. 1995.