Não informado. (1957). Bibliography and Subject Index of South African Geology. Geological Survey of South Africa.
Παραπομπή σε μορφή Chicago (17η εκδ.)Não informado. Bibliography and Subject Index of South African Geology. Pretoria, Africa do Sul: Geological Survey of South Africa, 1957.
Παραπομπή σε μορφή MLA (8th εκδ.)Não informado. Bibliography and Subject Index of South African Geology. Geological Survey of South Africa, 1957.
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