1. Department of Clinical Science and Services; The Royal Veterinary College; Hawkshead Lane North Mymms Hatfield Herts AL9 7TA UK
2. Department of Small Animal Clinical Sciences, College of Veterinary Medicine; Michigan State University; East Lansing MI 48824
3. Department of Clinical Sciences; Tufts Cummings School of Veterinary Medicine; North Grafton MA 01536 USA