Influenza in the world. 1 October 1990-30 September 1991.
D004196:Disease Outbreaks / Q000706:statistics & numerical data; D014943:Global Health; D006801:Humans; D009980:Influenza A virus / Q000302:isolation & purification; D009981:Influenza B virus / Q000302:isolation & purification; D007251:Influenza, Human / Q000453:epidemiology*