Van Wyngaardt, Wouter; Du Plessis, D.H.; Van Wyngaardt, Sandra(Published by the Agricultural Research Council, Onderstepoort Veterinary Institute., 1992)
Spencer, J.A.; Van Dijk, A.A.; Horzinek, Marian C.; Egberink, H.F.; Bengis, Roy G.; Keet, D.F.; Morikawa, S.; Bishop, D.H.L.(Published by the Agricultural Research Council, Onderstepoort Veterinary Institute., 1992)
De Lisle, G.W.; Collins, D.M.; Huchzermeyer, Hildegard F.A.K.(Published by the Agricultural Research Council, Onderstepoort Veterinary Institute., 1992)