Lee, Seung-Hwan. “Effect of Fine Sand Size in a Decentralized Household Drinking Water Purification Svstem”. Science & Technology Asia 11, no. 3 (October 31, 2015): 45–53. Accessed April 20, 2024. https://ph02.tci-thaijo.org/index.php/SciTechAsia/article/view/41543.