Richards, J. C., Hull, J., & Proctor, S. (1994). Changes: English for international communication : student's book 1. Cambridge: Cambridge University Press.
शिकागो स्टाइल उद्धरणRichards, Jack C., Jonathan Hull, और Susan Proctor. Changes: English for International Communication : Student's Book 1. Cambridge: Cambridge University Press, 1994.
एमएलए उद्धरणRichards, Jack C., Jonathan Hull, और Susan Proctor. Changes: English for International Communication : Student's Book 1. Cambridge: Cambridge University Press, 1994.
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