Galen JE, Gomez-Duarte OG, Losonsky GA, Halpern JL, Lauderbaugh CS, Kaintuck S, Reymann MK, Levine MM. A murine model of intranasal immunization to assess the immunogenicity of attenuated Salmonella typhi live vector vaccines in stimulating serum antibody responses to expressed foreign antigens. Vaccine. 1997; 15(6-7):700-8.