Clutton R E, Boyd C, Richards D L, Welker F W, Modransky P
Virginia Maryland Regional College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg 24061, USA.
Equine Vet J Suppl. 1992 Feb(11):30-3. doi: 10.1111/j.2042-3306.1992.tb04768.x.