Pimolsiri Supasatienchai, Jongruk Chanchareonsook, and Ed Sarobol. 2010. “Utilization of Slop Ash as a Source of Potassium for Corn Grown on the Pakchong Soil Series”. Agriculture and Natural Resources 44 (1). Bangkok, Thailand:17-23. https://li01.tci-thaijo.org/index.php/anres/article/view/244876.