National water well Association. (1985). Well drilling manual. National water well Association.
शिकागो स्टाइल उद्धरणNational water well Association. Well Drilling Manual. India: National water well Association, 1985.
एमएलए उद्धरणNational water well Association. Well Drilling Manual. National water well Association, 1985.
चेतावनी: ये उद्धरण हमेशा 100% सटीक नहीं हो सकते हैं.