Siebörger, R. F. (1975). The recruitment and organization of African labor for the Kimberley Diamond Mines, 1871-1888.
Chicago-viite (17. p.)Siebörger, Robert Frederick. The Recruitment and Organization of African Labor for the Kimberley Diamond Mines, 1871-1888. 1975.
MLA-viite (8. p.)Siebörger, Robert Frederick. The Recruitment and Organization of African Labor for the Kimberley Diamond Mines, 1871-1888. 1975.
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