Michael Duckworth, & Michael Duckworth; Kathy Gude. (1999). Countdown to first certificate: Workbook : with key and tapescripts. Oxford: Oxford University Press.
استشهاد بنمط شيكاغوMichael Duckworth, و Michael Duckworth; Kathy Gude. Countdown to First Certificate: Workbook : With Key and Tapescripts. Oxford: Oxford University Press, 1999.
MLA استشهادMichael Duckworth, و Michael Duckworth; Kathy Gude. Countdown to First Certificate: Workbook : With Key and Tapescripts. Oxford: Oxford University Press, 1999.
تحذير: قد لا تكون هذه الاستشهادات دائما دقيقة بنسبة 100%.