1[1]Michael R. Muirhead ,Thomas I. L. Alexander. Management pig health and the treatment of disease. 5M Enterprises Limited.United Kingdom 1997
2[2]Barbara E. Straw, Sylvie D'Allaire , William L. Mengeling,David J. Taylor,8th Edition,Diseases of Swine, Iowa State University Press/Ames,Iowa,U.S.A.1999
