9Schelling E, Thur B, Griot C, et al. Epidemiological study of Newcastle disease in backyard poultry and wild bird population in Switzerland Avian Pathology [J]. 1999, 28(3) : 72-263.
10Arp L H, Domermuth C H, Pearson J E. A laboratory manual for the isolation and identification of avian pathogens [ M ]. 3rd eds. Dubuque, Iowa: Kendall/Hunt, 1989: 176-185.
