Terblanche, S.E. (Stephanus Esaias), 1940-(South African Society for Agricultural Extension, Department of Agriculture, Economics, Extensions and Rural Development, University of Pretoria, 2011)
Borman, M.E.; Nealer, E.J.; Stevens, Joseph Benjamin(South African Society for Agricultural Extension, Department of Agriculture, Ecomomics, Extensions and Rural Development, University of Pretoria, 2009)