Não informado. (1960). Information Circular. University of the Witwatersrand, Economic Geology Research Unit.
Style de citation Chicago (17e éd.)Não informado. Information Circular. Johannesburg, Africa do Sul: University of the Witwatersrand, Economic Geology Research Unit, 1960.
Style de citation MLA (8e éd.)Não informado. Information Circular. University of the Witwatersrand, Economic Geology Research Unit, 1960.
Attention : ces citations peuvent ne pas être correctes à 100%.