title: Comparison of the biological and serological properties of variola and vaccinia viruses.
mesh_terms: D000818:Animals; D006801:Humans; D066298:In Vitro Techniques; D051379:Mice; D014616:Vaccinia virus / Q000276:immunology* / Q000472:pathogenicity*; D012901:Variola virus / Q000276:immunology* / Q000472:pathogenicity*