World Health Organization. “Major Milestone Reached in Global Polio Eradication: Western Pacific Region Is Certified Polio-Free: WHO Press Release WHO 71 (29 October 2000)”. Communicable Diseases Intelligence, vol. 24, Oct. 2000, p. 304, https://ojs.cdi.cdc.gov.au/index.php/cdi/article/view/2606.