Bingham, J.; Foggin, Chris M.; Wandeler, A.I. (Alexander I.); Hill, F.W.G.(Published by the Agricultural Research Council, Onderstepoort Veterinary Institute, 1999)
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)