Ngwe, K. ., . I. . Kheoruenromne, and . A. Suddhiprakarn. “Potassium Status and Physicochemical and Mineralogical Properties of Lowland Vertisols in a Rice-Based Cropping System under Tropical Savanna Climate”. Agriculture and Natural Resources, vol. 46, no. 4, Aug. 2012, pp. 522-37, https://li01.tci-thaijo.org/index.php/anres/article/view/242906.