Duckworth, M., & Michael Duckworth; Kathy Gude. (1999). Countdown to First Certificate: Workbook with key and tapescripts. Oxford: Oxford University Press.
シカゴスタイル引用形Duckworth, Michael, , Michael Duckworth; Kathy Gude. Countdown to First Certificate: Workbook With Key and Tapescripts. Oxford: Oxford University Press, 1999.
MLA引用形式Duckworth, Michael, , Michael Duckworth; Kathy Gude. Countdown to First Certificate: Workbook With Key and Tapescripts. Oxford: Oxford University Press, 1999.
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