Twedt D C, Cuddon P A, Horn T W
Department of Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins 80523, USA.
J Vet Intern Med. 1999 Nov-Dec;13(6):613-6. doi: 10.1892/0891-6640(1999)013<0613:bwseia>2.3.co;2.