treatments ..., and its flu chief said the swine flu epidemic was still spreading. Nebehay, Stephanie. WHO admits shortcomings in handling flu pandemic. 路透社.
[2020-12-07]. (原始内容存档于2021-02-20) (英语). Lizzie Wade. From Black Death to fatal flu, past pandemics show why people on the margins suffer most. 《科学》(Science