. "CN" . "PROTEIN CELL" . "1674-800X" . "1" . "459" . "467" . "10.1007/s13238-010-0059-1" . "Crystal structure of the swine-origin A (H1N1)-2009 influenza A virus hemagglutinin (HA) reveals similar antigenicity to that of the 1918 pandemic virus" . . . . . . . . . . . . .