Não informado. (1957). Bibliography and Subject Index of South African Geology. Geological Survey of South Africa.
Chicago-Zitierstil (17. Ausg.)Não informado. Bibliography and Subject Index of South African Geology. Pretoria, Africa do Sul: Geological Survey of South Africa, 1957.
MLA-Zitierstil (8. Ausg.)Não informado. Bibliography and Subject Index of South African Geology. Geological Survey of South Africa, 1957.
Achtung: Diese Zitate sind unter Umständen nicht zu 100% korrekt.