ATTEMPT TO APPLY THE RESULTS OF SEROLOGICAL SURVEYS IN EPIDEMIOLOGICAL PRACTICE IN INFLUENZA.
D003604:Czechoslovakia; D003625:Data Collection; D004813:Epidemiology; D006385:Hemagglutination Inhibition Tests; D006664:History; D006801:Humans; D007251:Influenza, Human
CZECHOSLOVAKIA; EPIDEMIOLOGY; HEMAGGLUTINATION INHIBITION TESTS; HISTORY; INFLUENZA