3Urakawa S Studies on the antigenic variants of avian influenza A virus (A/tern/South Africa/61, Hay 5 Nay 2) obtained in the presence of homologous antiserum [J]. Japanese-Journal-of-Veterinary-Research, 1997,25 ( 1 ) :33.
4Robinson J H etc. Avian influenza virus infection of the immunosuppressed turedy[J].American - Journal - of - Veterinary - Research,1979, 40(9):219-222.
