Ries, A. (1996). Focus: The feature of your company depends on it. Harper Collins Publishers.
शिकागो स्टाइल उद्धरणRies, AI. Focus: The Feature of Your Company Depends on It. New York: Harper Collins Publishers, 1996.
एमएलए उद्धरणRies, AI. Focus: The Feature of Your Company Depends on It. Harper Collins Publishers, 1996.
चेतावनी: ये उद्धरण हमेशा 100% सटीक नहीं हो सकते हैं.