Du Plessis, D.H.; Van Wyngaardt, Wouter; Romito, M.; Du Plessis, M.(Pretoria : Agricultural Research Council, Onderstepoort Veterinary Institute, 1999)
Bingham, J.; Foggin, Chris M.; Wandeler, A.I. (Alexander I.); Hill, F.W.G.(Published by the Agricultural Research Council, Onderstepoort Veterinary Institute, 1999)
Bingham, J.; Foggin, Chris M.; Wandeler, A.I. (Alexander I.); Hill, F.W.G.(Published by the Agricultural Research Council, Onderstepoort Veterinary Institute, 1999)