Niamkaeo, S. ., & Robert, O. . (2020). 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(3), 275–282. Retrieved from https://ph02.tci-thaijo.org/index.php/ennrj/article/view/240574