Helgesen, M., & Brown, S. (1999). Active listening: Building skills for understanding : Level 2 [Đĩa CD-ROM]. Cambridge: Cambridge University Press.
शिकागो स्टाइल उद्धरणHelgesen, Marc, और Steven Brown. Active Listening: Building Skills for Understanding : Level 2 [Đĩa CD-ROM]. Cambridge: Cambridge University Press, 1999.
एमएलए उद्धरणHelgesen, Marc, और Steven Brown. Active Listening: Building Skills for Understanding : Level 2 [Đĩa CD-ROM]. Cambridge: Cambridge University Press, 1999.
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