s: A Political Economy of the Kalahari. Chicago: Chicago University Press, pp. 71–5. ISBN 9780226900155↑ Denbow, James (1986). "A New Look at the Later Prehistory of the Kalahari". The Journal of African History. 27 (1): 3–28. doi:10.1017/S0021853700029170. JSTOR 181334. S2CID 163079138.↑ Denbow, James; Klehm, Carla; Dussubieux, Laure (April 2015). "The glass beads of Kaitshàa and early Indian Ocean trade into the far interior of southern Africa". Antiquity (ඉංග්‍රීසි බසින්). 89 (344): 361–377. doi:10.15184/aqy.2014.50. ISSN 0003-598X. S2CID 161212483.↑ Hall, Martin (1990), Farmers, Kings, and Traders: The People of Southern Africa, 200-1860, University of Chicago Press. ISBN 0-226-31326-3.↑ Hall, Martin (1990), Farmers, Kings, and Traders: The People of Southern Africa, 200-1860, University of Chicago Press. ISBN 0-226-31326-3.↑ Hall, Martin (1990), Farmers, Kings, and Traders: The People of Southern Africa, 200-1860, University of Chicago Press. ISBN 0-226-31326-3.↑ Magan