title: Viral investigation of the 1968-69 Hong Kong influenza epidemic in Ceylon.
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D005260:Female; D006723:Hong Kong; D006801:Humans; D007251:Influenza, Human / Q000453:epidemiology / Q000382:microbiology*; D008297:Male; D009975:Orthomyxoviridae / Q000302:isolation & purification*; D013188:Sri Lanka