4Donatelli I, Campitelli L, et al. Detection of two antigenic subpopulations ofA (H1N1) influenza viruses from pigs: antigenic drift or interspecies transmission?. J Med Virol, 1991, 34(4): 248- 257
5Kida H, Ito T, et al. Potential for transmission of avian influenza viruses to pigs. J Gen Virol, 1994, 75(9): 2183-2188
6Ito T, Couceiro J S, Kelm S, et al. Molecular basis for the generation in pigs of influenza A viruses with pandemic potential. J Virol,1998, 72(9): 7367-7373
7Schultz U, Fitch W M, et al. Evolution of pig influenza viruses. Virology, 1991, 183(1): 61-73
8Mancini G, Donatelli I, Rozera C, et al. Antigenic and biochemical analysis of influenza A H3N2 viruses isolated from pigs. Arch Virol, 1985, 83(3-4): 57-167
9Ottis K, Sidoli L, Bachmann P A, et al. Human influenza A viruses in pigs: isolation of a H3N2 strain antigenically related to A/England/42/72 and evidence for continuous circulation of human viruses in the pig population. Arch Virol, 1982, 73(2): 103- 108
10Rota P A, Rocha E P, Harmon M W, et al. Laboratory characterization of a swine influenza virus isolated from a fatal case of human influenza. J Clin Microbiol, 1989, 27(6): 1413- 1416
