Van Halderen, A.; Van Rensburg, W.J.J.; Geyer, A.; Vorster, J.H. (Jan Harm)(Published by the Agricultural Research Council, Onderstepoort Veterinary Institute, 1994)
Botha, C.J. (Christoffel Jacobus); Van der Lugt, Jaco J.; Erasmus, G.L.; Kellerman, T. Stephanus; Schultz, R.A. (Rowena Anitra)(Published by the Agricultural Research Council, Onderstepoort Veterinary Institute, 1997)