Helman R G, Stair E L, Lehenbauer T W, Rodgers S, Saliki J T
Oklahoma Animal Disease Diagnostic Laboratory and the Department of Infectious Diseases and Physiology, Oklahoma State University, Stillwater, USA.
J Vet Diagn Invest. 1998 Jul;10(3):292-5. doi: 10.1177/104063879801000314.