A fatal case of diphtheria in Belgium, 24 March 2016, https://ecdc.europa.eu/sites/portal/files/media/en/publications/Publications/RRA-Diphtheria-Belgium.pdf][7: 2016 WHO/UNICEF Estimates of National Immunization Coverage http://www.who.int/immunization/monitoring_surveillance/who-immuniz.pdf?ua=1]
[6: ECDC. A fatal case of diphtheria in Belgium, 24 March 2016, (Egy végzetes himlő okozta megbetegedés esete Belgiumban, 2016. március 24)https://ecdc.europa.eu/sites/portal/files/media/en/publications/Publications/RRA-Diphtheria-Belgium.pdf][7: 2016 WHO/UNICEF Estimates of National Immunization Coverage (A WHO/UNICEF 2016-os becslései a nemzeti átoltottsági szintekről)http://www.who.int/immunization/monitoring_surveillance/who-immuniz.pdf?ua=1]