1. Al-Shaddebi, A. M. (1978). Ticks and tick-borne diseases in the ruminant in the UK and the Yemen Arab Republic, M.Sc. Thesis, University College of North Wales, Bangor.
2. Amerault, T. E. &Roby, T. O. (1968).Journal of the American Veterinary Medical Association,153, 1828–1834.
3. Barnett, S. F. (1977).Parasitic Protozoa, Vol. IV (Ed. J. P. Kreier), New York Academic Press, p. 77.
4. Boid, R., Jones, T. W. &Luckins, A. G. (1985).British Veterinary Journal,141, 87–105.
5. Dequin, H. (1973).World Atlas of Agriculture, Volume 2,Asia and Oceania, Instituto Geografico de Agostini-Novara, pp. 552–557.