Wan Kamarudin, W. F., Z. Irwan, M. R. Yaafar, and A. R. Mat Amin. “Lockdown Effect on Carbon Monoxide Concentration over Malaysia and Indonesia”. Scientific Review Engineering and Environmental Sciences (SREES), vol. 31, no. 2, June 2022, pp. 124-3, doi:10.22630/srees.2238.