1. Armour J, Bairden K, Batty AF, Davison CC, Ross D (1985) Persistent anthelmintic activity of ivermectin in cattle. Vet. Rec. 116:151–153.
2. Barth D (1983) Persistent anthelmintic effect of ivermectin in cattle. Vet. Rec. 113:300.
3. Benz GW and Ernst JV (1979) Anthelmintic activities of the B1a fraction of avermectin against gastrointestinal nematodes in calves. Am. J. Vet. Res. 40:1187–1188.
4. Bremner KC, Berrie DA, Hotson IK (1983) Persistence of the anthelmintic activity of ivermectin in calves. Vet. Rec. 113:569.
5. De Chaneet GC, Casey R, Dixon FF, Besier RB, Mitchell RK (1988) Effect of avermectin B1 and benzimidazole anthelmintics on worm egg output of treated cattle. Austral. Vet. J. 65:85–86.