1. Acocks, J.P.H. 1953. Veld types of South Africa. Memoris of the Botanical Survey of South Africa 28: 1?192.
2. Archer, S.F. 1994. Economic perspectives on Karoo economy. Arid Zone Ecology Forum abstracts, Foundation for Research Development, Pretoria, pp. 39?40.
3. Barnes, D.L. 1990. A survey of grazed and ungrazed grassland in the south-eastern Transvaal highveld. I. Palatability composition and grazing capacity. Journal of the Grassland Society of Southern Africa 7(4): 217?222.
4. Beukman, R.P. 1991. The role of nurse plants in the vegetation dynamics of the succulent Karoo. MS thesis, University of Cape Town, South Africa.
5. Bond, W.J., W.D. Stock and M.T. Hoffman. 1994. Has the Karoo spread? A test for desertification using carbon isotopes from soils. South African Journal of Science 90(7): 391?397.