Tan, S. Y., S. P. Teo, M. S. Abdullah, P. L. Chong, R. Asli, B. I. Mani, N. R. Momin, A. C. A. Lim, N. A. Rahman, C. F. Chong, and V. H. Chong. “COVID-19 Symptom Duration: Associations With Age, Severity and Vaccination Status in Brunei Darussalam, 2021”. Western Pacific Surveillance and Response, vol. 13, no. 4, Nov. 2022, p. 9, doi:10.5365/wpsar.2022.13.4.941.