Kotze, Sanet H.; Van der Merwe, N.J.; Van Aswegen, G.; Smith, G.A.(Published by the Agricultural Research Council, Onderstepoort Veterinary Institute., 1992)
Smuts, M.M.S. (Malie Marie Sophie), 1933-; Bezuidenhout, A.J. (Abraham Johannes), 1942-(Published by the Agricultural Research Council, Onderstepoort Veterinary Institute., 1992)