Botha, C.J. (Christoffel Jacobus); Schultz, R.A. (Rowena Anitra); Van der Lugt, Jaco J.; Retief, E.; Labuschagne, Leonie(Published by the Agricultural Research Council, Onderstepoort Veterinary Institute, 1999)
Trichard, C.J.V.; Jordaan, P.; Jacobsz, Elsie P.; Henton, Marijke M.(Published by the Agricultural Research Council, Onderstepoort Veterinary Institute, 1993)