Vangnai, S., Attanandana, T. and Tawateekul, A. (1974) “Sulfide Formation and Rice Yield in Ongkarak Soil”, Agriculture and Natural Resources. Bangkok, Thailand, 8(1), pp. 23–27. available at: https://li01.tci-thaijo.org/index.php/anres/article/view/240676 (accessed: 19 September 2026).