Não informado. (1964). Coal, gold and base minerals of Southern Africa. Pithead Press.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रNão informado. Coal, Gold and Base Minerals of Southern Africa. Johannesburg, Africa do Sul: Pithead Press, 1964.
एमएलए (8वां संस्करण) प्रशस्ति पत्रNão informado. Coal, Gold and Base Minerals of Southern Africa. Pithead Press, 1964.
चेतावनी: ये उद्धरण हमेशा 100% सटीक नहीं हो सकते हैं.