Não informado. (1990). Research Journal of the Water Pollution Control Federation. Water Pollution Control Federation.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रNão informado. Research Journal of the Water Pollution Control Federation. Alexandria, Va: Water Pollution Control Federation, 1990.
एमएलए (8वां संस्करण) प्रशस्ति पत्रNão informado. Research Journal of the Water Pollution Control Federation. Water Pollution Control Federation, 1990.
चेतावनी: ये उद्धरण हमेशा 100% सटीक नहीं हो सकते हैं.