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)
Botha, C.J. (Christoffel Jacobus); Kellerman, T. Stephanus; Schultz, R.A. (Rowena Anitra); Erasmus, G.L.; Retief, E.P.(Published by the Agricultural Research Council, Onderstepoort Veterinary Institute, 1998)
Miles, Christopher O.; Wilkins, A.L.; Erasmus, G.L.; Kellerman, T. Stephanus(Published by the Agricultural Research Council, Onderstepoort Veterinary Institute, 1994)