Duckworth, M. (2008). Countdown to first certificate: (Student's book). Oxford: Oxford University Press.
Trích dẫn kiểu ChicagoDuckworth, Michael. Countdown to First Certificate: (Student's Book). Oxford: Oxford University Press, 2008.
Deismireacht MLADuckworth, Michael. Countdown to First Certificate: (Student's Book). Oxford: Oxford University Press, 2008.
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