Xaysatith Souliyavongsa, Tasnee Attanandana, and Russell Yost. “Predicting Phosphorus Buffer Coefficients of Representative Maize Soils in Laos”. Agriculture and Natural Resources, vol. 44, no. 2, Apr. 2010, pp. 174-81, https://li01.tci-thaijo.org/index.php/anres/article/view/244903.