O'Neill, R., & Richard O'Neill. (2014). Unlock: Listening and speaking skills. Cambridge: Cambridge University Press.
शिकागो स्टाइल उद्धरणO'Neill, Richard, और Richard O'Neill. Unlock: Listening and Speaking Skills. Cambridge: Cambridge University Press, 2014.
एमएलए उद्धरणO'Neill, Richard, और Richard O'Neill. Unlock: Listening and Speaking Skills. Cambridge: Cambridge University Press, 2014.
चेतावनी: ये उद्धरण हमेशा 100% सटीक नहीं हो सकते हैं.