1. J. Oldham, Pig Farming (Oct suppl), 72–73 (1972)
2. M.B. Pensaert, S.G. Yeo, in Disease of Swine, ed. by B.E. Straw, J.J. Zimmerman, S. D’Allaire, D.J. Taylor (The Blackwell Publishing Professional, Ames, IA, 2006), pp. 367–372
3. C. Qinghua, N. Xiaoying, Y. Chengyu, J. Anim. Vet. Sci. 22(3), 22 (1992)
4. M.B. Pensaert, P. de Bouck, Arch. Virol. 58, 243–247 (1978)
5. P. de Bouck, M.B. Pensaert, Am. J. Vet. Res. 41, 219–223 (1980)