Nontananandh, S. ., and B. . Changnoi. “Internet GIS, Based on USLE Modeling, for Assessment of Soil Erosion in Songkhram Watershed, Northeastern of Thailand”. Agriculture and Natural Resources, vol. 46, no. 2, Apr. 2012, pp. 272-8, https://li01.tci-thaijo.org/index.php/anres/article/view/242812.