title: Possible origin of current influenza A H1N1 viruses.
authors.forename: Hong
authors.initials: H
authors.lastname: Zhang
authors.forename: Ling
authors.initials: L
authors.lastname: Chen
mesh_terms: D004196:Disease Outbreaks; D014943:Global Health; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000235:genetics*; D007251:Influenza, Human / Q000821:virology*