1. Armstrong, D.A., Miller, C.R., 1980. Liver flukes in cattle: life cycle, pathology, economic impact. Norden News, 30–33.
2. Survey of gastrointestinal parasitism in Wisconsin dairy cattle;Cox;J. Am. Vet. Med. Assoc.,1962
3. Dargie, J.D., 1987. The impact on production and the mechanisms of pathogenesis of trematode infections in cattle and sheep. In: Leaning, W.H.D., Guerrero, J. (Eds.), The Economic Impact of Parasitism in Cattle. Proc. MSD AGVET Symp., XXII World Vet. Cong., Montreal, Canada, pp. 35–43.
4. Gibbs, H.C., 1987. The effect of gastrointestinal nematodes on digestion and energy metabolism in calves. In: Leaning, W.H.A., Guerro, J. (Eds.), The Economic Impact of Parasitism in Cattle. Proc. MSD AGVET Symp., XXII World Vet. Cong., Montreal, Canada, pp. 35–43.
5. Control strategies for ruminant and equine parasites to counter resistance, encystment, and ecotoxicity in the USA;Herd;Vet. Parasitol.,1993