Sebadieta, Rapelang Bamba; Terblanche, S.E. (Stephanus Esaias), 1940-; Ngomane, Tsakani(South African Society for Agricultural Extension, Department of Agricultural Ecomomics, Extension and Rural Development, University of Pretoria, 2007)
Zwane, E.M.; Duvel, G.H. (Gustav Heinrich)(South African Society for Agricultural Extension, Department of Agriculture, Ecomomics, Extensions and Rural Development, University of Pretoria, 2008)