1Witter R L. Increased virulence of Marek's disease virus filed isolates[J].Avian Dis. 1997, 41:149-163
2Witter R L. Control strategies for Marek's disease: A perspective for the future[J].Poultry Science, 1998, 77:1197-1203
3Witter R L. Pathogenicity of variant Marek's disease virus isolates in vaccinated and unvaccinated chickens[J].Avian Dis. 1980, 24:210-232
4Calnek B W,Harris R W,Buscaglia C, Schat K A, Lucia B. Relationship between the immuno-suppressive potential and the pathotype of Marek's disease virus isolates[J].Avian Dis. 1998, 42:124-132
