Chattaong, P., and Jutamas, M. “Heavy metal accumulation in scallion (Allium cepa var. aggregatum) fields in Uttaradit Province, Thailand”. International Journal of Agricultural Technology, vol. 16, no. 1, Jan. 2020, pp. 27-36, https://li04.tci-thaijo.org/index.php/IJAT/article/view/6156.