Não informado. (1946). Mining Survey. Transvaal and Orange Free State Chamber of Mines.
Chicagoスタイル(17版)引用形式Não informado. Mining Survey. Johannesburg, Africa do Sul: Transvaal and Orange Free State Chamber of Mines, 1946.
MLA(8版)引用形式Não informado. Mining Survey. Transvaal and Orange Free State Chamber of Mines, 1946.
警告: この引用は必ずしも正確ではありません.