1. Box, E. D. & McGuinness, T. B. (1978).Journal of Parasitology,64, 161–162.
2. Ginawi, M. A. & Shommein, A. M. (1977).Sudan Journal of Veterinary Science and Animal Husbandry,18, 92–97.
3. Munday, B. L. & Rickard, M. D. (1974).Australian Veterinary Journal,50, 558–559.
4. Seneviratna, P., Edward, A. G. & DeGiusti, D. L. (1975).American Journal of Veterinary Research,36, 337–339.