1. ABBOTT K. A. TAYLOR M. STUBBINGS L. S 2013 Sustainable Worm Control Strategies for Sheep 4th edn www.scops.org.uk/content/SCOPS-Technical-Manual-4th-Edition-updated-September-2013.pdf
2. AMTRA 2017 Zolvix: change of legal category www.amtra.org.uk
3. BVA 2017 Anthelmintic reclassification causes concern for vets www.bva.co.uk/news-campaigns-and-policy/newsroom/news-releases/anthelmintic-reclassification-causes-concern-for-vets
4. Sheep flock health planning and the role of sheep veterinary surgeons;GASCOIGNE;Livestock,2016
5. Anthelmintic efficacy on sheep farms in south-west England;GLOVER;Veterinary Record,2017