Minnaar, P.P.; McCrindle, Robert Ian; Naude, T.W.; Botha, C.J. (Christoffel Jacobus)(Published by the Agricultural Research Council, Onderstepoort Veterinary Institute ., 2000)
Pienaar, J. G.; Van der Westhuizen, G.C.A.; Anderson, L.A.P.; Naude, T.W.; Kellerman, T. Stephanus(Published by The Government Printer, Pretoria, 1976)