Duckworth, M., & Gude, K. (1999). Countdown to first certificate: Student's book. Oxford: Oxford University Press.
Παραπομπή Chicago StyleDuckworth, Michael., και Kathy Gude. Countdown to First Certificate: Student's Book. Oxford: Oxford University Press, 1999.
Παραπομπή MLADuckworth, Michael., και Kathy Gude. Countdown to First Certificate: Student's Book. Oxford: Oxford University Press, 1999.
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