Niamkaeo S, Robert O. Spatial Relationship of Drug Smuggling in Northern Thailand Using GIS-based Knowledge Discovery: DOI: 10.32526/ennrj.18.3.2020.26. Environ. Nat. Resour. J. [internet]. 2020 Apr. 20 [cited 2026 Aug. 27];18(3):275-82. available from: https://ph02.tci-thaijo.org/index.php/ennrj/article/view/240574