1. Armour, J., Jarrett, W. F. H. & Jennings, F. W. Am. J. Vet. Res. 27, 1267–1278(1966).
2. Meyer, K. Genet. Selec. Evol. 21, 317–330(1989).
3. Bishop, S. C., Bairden, K., McKellar, Q. A., Park, M. & Stear, M. J. Anim. Sci. 63, 423–428(1996).
4. Stear, M. J. et al. Parasite Immunol. 17, 643–652(1995).
5. McCririe, L. et al. Parasite Immunol. 19, 235–242(1997).