APA aipamena

Duckworth, M. (2008). Countdown to first certificate: (Student's book). Oxford: Oxford University Press.

Chicago Style aipamena

Duckworth, Michael. Countdown to First Certificate: (Student's Book). Oxford: Oxford University Press, 2008.

MLA aipamena

Duckworth, Michael. Countdown to First Certificate: (Student's Book). Oxford: Oxford University Press, 2008.

Kontuz: berrikusi erreferentzia hauek erabili aurretik.