UNG, Trang thi Hong et al. Occurrence of the Omicron variant of SARS-CoV-2 in northern Viet Nam in early 2022. Western Pacific Surveillance and Response, Manila, Philippines, v. 13, n. 3, 2022. DOI: 10.5365/wpsar.2022.13.3.955. Disponível em: https://ojs.wpro.who.int/ojs/index.php/wpsar/article/view/955. Acesso em: 3 jun. 2026.