Duckworth, M., & Michael Duckworth; Kathy Gude. (1999). Countdown to First Certificate: Workbook with key and tapescripts. Oxford: Oxford University Press.
Trích dẫn kiểu ChicagoDuckworth, Michael, và Michael Duckworth; Kathy Gude. Countdown to First Certificate: Workbook With Key and Tapescripts. Oxford: Oxford University Press, 1999.
Deismireacht MLADuckworth, Michael, và Michael Duckworth; Kathy Gude. Countdown to First Certificate: Workbook With Key and Tapescripts. Oxford: Oxford University Press, 1999.
Rabhadh: D'fhéadfadh nach mbeadh na deismireachtaí seo 100% cruinn i gcónaí.