Yoothong, K., M. Pukamphol, and A. Hutspardol. “ Illite and Montmorillonite in the Coarse and the Fine Clay Fractions in Some Alluvial Soils”. Agriculture and Natural Resources, vol. 20, no. 3, Sept. 1986, pp. 285-99, https://li01.tci-thaijo.org/index.php/anres/article/view/242671.