LIU, Xiaojia. The Economic Environment and Black Swan Events: Taking COVID-19 as an example. Journal of Education, Humanities and Social Sciences, [S. l.], v. 23, p. 336–341, 2023. DOI: 10.54097/ehss.v23i.12916. Disponível em: https://drpress.org/ojs/index.php/EHSS/article/view/12916. Acesso em: 31 aug. 2026.