title: The influenza pandemic of 1918-1919 in the perspective of a half century.
mesh_terms: D004196:Disease Outbreaks; D049673:History, 20th Century; D006801:Humans; D007251:Influenza, Human / Q000453:epidemiology* / Q000266:history; D009975:Orthomyxoviridae; D012189:Retrospective Studies