Botha, C.J. (Christoffel Jacobus); Schultz, R.A. (Rowena Anitra); Van der Lugt, Jaco J.; Retief, E.; Labuschagne, Leonie(Published by the Agricultural Research Council, Onderstepoort Veterinary Institute, 1999)
Minnaar, P.P.; McCrindle, Robert Ian; Naude, T.W.; Botha, C.J. (Christoffel Jacobus)(Published by the Agricultural Research Council, Onderstepoort Veterinary Institute ., 2000)