Sangchay, W., and K. Ubolchollakhat. “Photocatalytic and antibacterial activities of ZnO powders prepared via a sol-gel method”. Engineering and Applied Science Research, vol. 43, no. 1, Jan. 2016, pp. 21-25, https://ph01.tci-thaijo.org/index.php/easr/article/view/35409.