1VINES A,WELLS K,MATROSOVICH M,et al.The role of influenza Avirus hemagglutinin residues 226 and 228 in receptor specificity and host range restriction[J].J Virol,1998,72:7621-7626.
2WEBSTER RG,BEAN WJ,GORAMAN W T.Evolufion and ecology of influenza a viruses[J].Microbiological Reviews,1992,6(1):152-179.
