Duckworth, M. (2009). 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, 2009.
MLA引文Duckworth, Michael. Countdown to First Certificate: (Student's Book). Oxford: Oxford University Press, 2009.
警告：这些引文格式不一定是100％准确.