Sthiannopkao, S., S. Takizawa, and W. Wirojanagud. “Assessment of Seasonal Variations of Surface Water Quality in the Phong Watershed, Thailand”. Science & Technology Asia, vol. 12, no. 4, Oct. 2015, pp. 36-43, https://ph02.tci-thaijo.org/index.php/SciTechAsia/article/view/41481.