World Health Organization (WHO). Assessment report of the Global Vaccine Action Plan. Strategic Advisory Group of Experts on Immunization. Retrieved (1 Mar 2022). http://www.who.int/immunization/web_2017_sage_gvap_assessment_report_en.pdf (2017).
World Health Organization (WHO). Assessment report of the Global Vaccine Action Plan. Strategic Advisory Group of Experts on Immunization. Retrieved (1 Mar 2022). http://www.who.int/immunization/web_2017_sage_gvap_assessment_report_en.pdf (2017).