Odendaal, M.W.; Pieterson, P.M.; De Vos, Valerius; Botha, A.D.(Published by the Agricultural Research Council, Onderstepoort Veterinary Institute., 1991)
Fourie, Niel; Bastianello, Stella S.; Nel, P.W.; Kellerman, T. Stephanus(Published by the Agricultural Research Council, Onderstepoort Veterinary Institute., 1991)
Scholtz, M.M.; Spickett, Arthur M.; Lombard, P.E.; Enslin, C.B.(Published by the Agricultural Research Council, Onderstepoort Veterinary Institute., 1991)