Niamkaeo, Sumethat, and Ornprapa Robert. “Spatial Relationship of Drug Smuggling in Northern Thailand Using GIS-Based Knowledge Discovery: DOI: 10.32526/Ennrj.18.3.2020.26”. Environment and Natural Resources Journal 18, no. 3 (April 20, 2020): 275–282. Accessed May 3, 2024. https://ph02.tci-thaijo.org/index.php/ennrj/article/view/240574.