5BEARD C.W, SCHNITZLEIM W M, TRIPATHY D N. protection of chickens a- gainst highly pathogenic avian influenza virus (H5N2) by recombinant fowl pox viruses.Avian Dis,1991.35:356-359.
6CHAMBELLS T,KAWAOKA Y, WEBSTER R G.Protection of chickens from lethal influenza infection by Vaccinia expressed hemagglutinin [J].Virology, 1988.167:414-421.
8Swayne D E,Beck J R,Kinney N.Failure of a recombinant fowl poxvirus vaccine con- taimng an avian influenza hemagglutinin gene to provide consistent protection against influenza in chickens pre-immunized with a fowlpox vaccine [J].Avian disease,2000,44: 132-137.