Duckworth, M. (2008). Countdown to first certificate: (Student's book). Oxford: Oxford University Press.
Dyfyniad Arddull ChicagoDuckworth, Michael. Countdown to First Certificate: (Student's Book). Oxford: Oxford University Press, 2008.
Dyfyniad MLADuckworth, Michael. Countdown to First Certificate: (Student's Book). Oxford: Oxford University Press, 2008.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.