Cita APA

Duckworth, M., & Gude, K. (1999). Countdown to first certificate: Student's book. Oxford: Oxford University Press.

Citación estilo Chicago

Duckworth, Michael., y Kathy Gude. Countdown to First Certificate: Student's Book. Oxford: Oxford University Press, 1999.

Cita MLA

Duckworth, Michael., y Kathy Gude. Countdown to First Certificate: Student's Book. Oxford: Oxford University Press, 1999.