A Single Amino Acid in the HA of pH1N1 2009 Influenza Virus Affects Cell Tropism in Human Airway Epithelium, but Not Transmission in Ferrets - van, Doremalen N; Shelton, H; Roberts, KL; Jones, IM; Pickles, RJ; Thompson, CI; Barclay, WS (PLOS ONE, 2011)