Doff, A., & Jones, C. (1997). Language in use: Upper-intermediate : self-study workbook with answer key (1st print.). Cambridge University Press.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रDoff, Adrian, और Christopher Jones. Language in Use: Upper-intermediate : Self-study Workbook with Answer Key. 1st print. Cambridge: Cambridge University Press, 1997.
एमएलए (8वां संस्करण) प्रशस्ति पत्रDoff, Adrian, और Christopher Jones. Language in Use: Upper-intermediate : Self-study Workbook with Answer Key. 1st print. Cambridge University Press, 1997.
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