Kempton, Daniel R.; Roni L. Du Preez (December 1997). "Namibian-De Beers State-Firm Relations: Cooperation and Conflict". Journal of Southern African Studies. 23 (4). Taylor & Francis, Ltd.: 585–613. doi:10.1080/03057079708708559. JSTOR2637428.
jstor.org
Kempton, Daniel R.; Roni L. Du Preez (December 1997). "Namibian-De Beers State-Firm Relations: Cooperation and Conflict". Journal of Southern African Studies. 23 (4). Taylor & Francis, Ltd.: 585–613. doi:10.1080/03057079708708559. JSTOR2637428.