Não informado. (2021). Technical Literature Abstracts. American Petroleum Institute.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रNão informado. Technical Literature Abstracts. New York: American Petroleum Institute, 2021.
एमएलए (8वां संस्करण) प्रशस्ति पत्रNão informado. Technical Literature Abstracts. American Petroleum Institute, 2021.
चेतावनी: ये उद्धरण हमेशा 100% सटीक नहीं हो सकते हैं.