Worthington, R.W.; Bigalke, R.D.(Published jointly by the Agricultural Research Council, ARC-Onderstepoort Veterinary Institute and the Faculty of Veterinary Science, University of Pretoria., 2001)
Bragg, R.R. (Robert Richard)(Published jointly by the Agricultural Research Council, ARC-Onderstepoort Veterinary Institute and the Faculty of Veterinary Science, University of Pretoria., 2002)