NGUYEN, Hang Khanh Le et al. Virological characteristics of cases of COVID-19 in northern Viet Nam, January–May 2020. Western Pacific Surveillance and Response, Manila, Philippines, v. 12, n. 4, 2021. DOI: 10.5365/wpsar.2021.12.4.833. Disponível em: https://ojs.wpro.who.int/ojs/index.php/wpsar/article/view/833. Acesso em: 3 jun. 2026.