Spickett, Arthur M.; Bagnall, R.J.; Uys, A.C. (André Charles)(Published by the Agricultural Research Council, Onderstepoort Veterinary Institute, 1995)
Van der Merwe, N.J.; Bezuidenhout, A.J. (Abraham Johannes), 1942-; Seegers, Christine D.(Published by the Agricultural Research Council, Onderstepoort Veterinary Institute, 1995)