GUPTA O P. (2019). Elements of Water Pollution Control Engineering (1st.). KHANNA PUBLICATION.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रGUPTA O P. Elements of Water Pollution Control Engineering. 1st. NEW DELHI: KHANNA PUBLICATION, 2019.
एमएलए (9वां संस्करण) प्रशस्ति पत्रGUPTA O P. Elements of Water Pollution Control Engineering. 1st. KHANNA PUBLICATION, 2019.
चेतावनी: ये उद्धरण हमेशा 100% सटीक नहीं हो सकते हैं.