5Zimmer SM,Burke DS. Historical perspective -emergence of influenza A ( H1 N 1 ) viruses [ J ]. N Engl J Med,2009,361 ( 3 ) : 279 - 285.
6Centers for Disease Control and Prevention(CDC). Swine- origin influenza A( H1 N1 )virus infections in a school -New York City April 2009 [ J ]. Morb Mortal Wkly Rep ,2009,58 ( 17 ) :470 - 472.
7Komiya N ,Gu Y,Kamiya H ,et al. Clinical features of cases of influenza A ( H1 N1 ) v in Osaka prefecture ,Japan May 2009 [ J ]. Euro Surveill,2009, 14(29) pii :19 272.
8Kumar A,Zarychanski R,Pinto R,et al. Canadian Critical Care Trials Group H1N1 Collaborative, critically ill patients with 2009 influenza A( H1N1 ) infection in Canada[ J ]. JAMA ,2009,302 ( 17 ) : 1872 - 1879.
