WHO--the days of the mass campaigns.
Williams
G
G
D003140:Communicable Disease Control / Q000266:history*; D005193:Family Planning Services; D049673:History, 20th Century; D006801:Humans; D012899:Smallpox / Q000517:prevention & control; D012900:Smallpox Vaccine; D014944:World Health Organization / Q000266:history*
D012900:Smallpox Vaccine