Não informado. Drilling mud. National Lead, Baroid Sales Division.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रNão informado. Drilling Mud. Houston, Tex: National Lead, Baroid Sales Division.
एमएलए (8वां संस्करण) प्रशस्ति पत्रNão informado. Drilling Mud. National Lead, Baroid Sales Division.
चेतावनी: ये उद्धरण हमेशा 100% सटीक नहीं हो सकते हैं.