Tianmanee, K., S. Wongpichet, E. Taira, and M. Ueno. “The Study of the Soil Texture Parameter in the Upland of Khon Kaen Province; Thailand”. Engineering and Applied Science Research, vol. 43, Nov. 2016, pp. 354-8, https://ph01.tci-thaijo.org/index.php/easr/article/view/70249.