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)
Mushi, E.Z.; Isa, J.F.W.; Chabo, R.G.; Binta, M.G.; Kapaata, R.W.; Ndebele, R.T.; Chakalisa, K.C.(Published by the Agricultural Research Council, Onderstepoort Veterinary Institute, 1998)