Siebörger, R. F. (1975). The recruitment and organization of African labor for the Kimberley Diamond Mines, 1871-1888.
Chicago-referens (17:e uppl.)Siebörger, Robert Frederick. The Recruitment and Organization of African Labor for the Kimberley Diamond Mines, 1871-1888. 1975.
MLA-referens (8:e uppl.)Siebörger, Robert Frederick. The Recruitment and Organization of African Labor for the Kimberley Diamond Mines, 1871-1888. 1975.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.