Cita APA (7th ed.)

Owen, R. (1980). Countdown to english: An intermediate course for examinations. BBC.

Cita Chicago (17th ed.)

Owen, Roger. Countdown to English: An Intermediate Course for Examinations. Londres: BBC, 1980.

Cita MLA (9th ed.)

Owen, Roger. Countdown to English: An Intermediate Course for Examinations. BBC, 1980.