Simbi, B.H.; Peter, T.F.; Burridge, M.J.; Mahan, S.M.(Pretoria : Agricultural Research Council, ARC-Onderstepoort Veterinary Institute and the University of Pretoria, Faculty of Veterinary Science, 2003)
Kakono, O.; Hove, T.; Mahan, S.; Geysen, Dirk(Pretoria : Agricultural Research Council, ARC-Onderstepoort Veterinary Institute and the University of Pretoria, Faculty of Veterinary Science, 2003)