[On the problem of the duration of post-vaccinal immunity against smallpox].
DZHAVADOV
R B
RB
D006801:Humans; D007109:Immunity; D012899:Smallpox / Q000276:immunology*; D014611:Vaccination; D014612:Vaccines; D012901:Variola virus
D014612:Vaccines
SMALLPOX/immunology; VACCINATION