Poland, Gregory A.; Jacobson, Robert M. (13 January 2011). "The Age-Old Struggle against the Antivaccinationists". New England Journal of Medicine. 364 (2): 97–99. doi:10.1056/NEJMp1010594. PMID21226573.
Poland, Gregory A.; Jacobson, Robert M. (13 January 2011). "The Age-Old Struggle against the Antivaccinationists". New England Journal of Medicine. 364 (2): 97–99. doi:10.1056/NEJMp1010594. PMID21226573.