Andersen A A, Grimes J E, Shivaprasad H L
Avian and Swine Respiratory Diseases Research Unit, USDA Agricultural Research Service, National Animal Disease Center, Ames, IA 50010, USA.
J Vet Diagn Invest. 1998 Apr;10(2):186-8. doi: 10.1177/104063879801000214.