Bekker, Theo Frederik; Kaiser, Clive; Labuschagne, Nico(South African Society of Crop Production/ Soil Science Society of South Africa/ South African Weed Science Society/ South African Society for Horticultural Sciences, 2009)
Du Plessis, Willemien (Wilhelmina), 1958-; Pienaar, Juanita (Juanita Magrietha), 1965-; Olivier, N.J.J. (Nicolaas Johannes Jacobus)(The Verloren van Themaat Centre for Public Law Studies, UNISA, 2009)