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)
Smuts, M.M.S. (Malie Marie Sophie), 1933-; Bezuidenhout, A.J. (Abraham Johannes), 1942-(Published by the Agricultural Research Council, Onderstepoort Veterinary Institute., 1992)