Bexfield Nicholas H, Watson Penny J, Herrtage Michael E
Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 OES, UK.
J Vet Intern Med. 2006 Nov-Dec;20(6):1487-90. doi: 10.1892/0891-6640(2006)20[1487:momguc]2.0.co;2.