Não informado. (1963). Annual Research Review. Chamber of Mines of South Africa.
Παραπομπή σε μορφή Chicago (17η εκδ.)Não informado. Annual Research Review. Johannesburg, Africa do Sul: Chamber of Mines of South Africa, 1963.
Παραπομπή σε μορφή MLA (8th εκδ.)Não informado. Annual Research Review. Chamber of Mines of South Africa, 1963.
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