Jansen van Rensburg, H.G. (Hester Getruida); Claassens, A.S. (Andries Stephanus), 1943-; Beukes, D.J.(South African Society of Crop Production/ Soil Science Society of South Africa/ Southern African Weed Science Society/ Southern African Society for Horticultural Sciences, 2009)
Jansen van Rensburg, H.G. (Hester Getruida); Claassens, A.S. (Andries Stephanus), 1943-; Beukes, D.J.; Weepener, H.L.; Beukes, P.J.(South African Society of Crop Production/ Soil Science Society of South Africa/ Southern African Weed Science Society/ Southern African Society for Horticultural Sciences, 2009)
Venter, A.; Smith, Marie F.; Beukes, D.J.; Claassens, A.S. (Andries Stephanus), 1943-; Van Meirvenne, M.(South African Society of Crop Production/ Soil Science Society of South Africa/ Southern African Weed Science Society/ Southern African Society for Horticultural Sciences, 2009)