1. Acocks, J.P.H., 1975. Veld Types of South Africa with Accompanying Veld Type Map. Memoirs of the Botanical Survey of South Africa, No. 40, 2nd Edition. Department of Agricultural Technical Services, Botanical Research Institute, South Africa, 128 pp.
2. Bath, G.F., 2000. Trial design and requirements — commercial farms. In: Anonymous (Ed.), FAO TCP Workshop on Sustainable Worm Control Programmes for Sheep and Goats, Faculty of Veterinary Science, University of Pretoria, Pretoria, South Africa, June 2000.
3. Besier, R.B., 1997. Ecological selection for anthelmintic resistance: re-evaluation of sheep worm control programs. In: Van Wyk, J.A., Van Schalkwyk, P.C. (Eds.), Managing Anthelmintic Resistance in Endoparasites. Workshop held at the 16th International Conference of the World Association for the Advancement of Veterinary Parasitology, Sun City, South Africa, August 1997.
4. Efficacy of levamisole against immature and mature nematodes in goats with induced infections;Coles;Am. J. Vet. Res.,1989
5. World Association for the Advancement of Veterinary Parasitology (WAAVP) methods for the detection of anthelmintic resistance in nematodes of veterinary importance;Coles;Vet. Parasitol.,1992