Não informado. (1969). Minerals science and engineering. National Institute for Metallurgy.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रNão informado. Minerals Science and Engineering. Cottesloe, Africa do Sul: National Institute for Metallurgy, 1969.
एमएलए (8वां संस्करण) प्रशस्ति पत्रNão informado. Minerals Science and Engineering. National Institute for Metallurgy, 1969.
चेतावनी: ये उद्धरण हमेशा 100% सटीक नहीं हो सकते हैं.