Somewhere to start:

Try searching PLoS Pathogens article titles for "influenza":   title:( influenza )

ASM has made articles on H1N1 published within the past 6 months in ASM’s Journal of Virology, Journal of Clinical Microbiology, and Antimicrobial Agents and Chemotherapy freely available online.

BioMed Central: Influenza Gateway to Influenza A(H1N1) - selected articles

Antigenic and Genetic Characteristics of Swine-Origin 2009 A(H1N1) Influenza Viruses Circulating in Humans. Science. 2009 May 22.