APA aipamena

Duckworth, M. (2008). Countdown to first certificate: (Workbook CD). Oxford: Oxford University Press.

Chicago Style aipamena

Duckworth, Michael. Countdown to First Certificate: (Workbook CD). Oxford: Oxford University Press, 2008.

MLA aipamena

Duckworth, Michael. Countdown to First Certificate: (Workbook CD). Oxford: Oxford University Press, 2008.

Kontuz: berrikusi erreferentzia hauek erabili aurretik.