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)
D'Haese, M.F.C. (Marijke); Calus, M.; Kirsten, Johann F.; Van Huylenbroeck, Guido; Bostyn, F.(Agricultural Economics Association of South Africa, 2001-12)
Sartorius, Kurt; Kirsten, Johann F.(Independent Regulatory Board for Auditors (IRBA), SA Institute of Chartered Accountants (SAICA) & SA Association of Accountants (SAAA), 2004-06)