Witowitaya, A., P. Chuaybamroong, and S. Supothina. “Photocatalysis Disinfection of Bacillus Subtilis Spores in Water under Sunlight Irradiation”. Science & Technology Asia, vol. 19, no. 3, Sept. 2014, pp. 44-54, https://ph02.tci-thaijo.org/index.php/SciTechAsia/article/view/21439.