Richards, J. C., Hull, J., & Proctor, S. (1998). Changes: English for international communication : INTRO teacher's book. Cambridge: Cambridge University Press.
शिकागो स्टाइल उद्धरणRichards, Jack C., Jonathan Hull, और Susan Proctor. Changes: English for International Communication : INTRO Teacher's Book. Cambridge: Cambridge University Press, 1998.
एमएलए उद्धरणRichards, Jack C., Jonathan Hull, और Susan Proctor. Changes: English for International Communication : INTRO Teacher's Book. Cambridge: Cambridge University Press, 1998.
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