Supsomboon S. A Mathematical Model for Vehicle Routing of Used-oil Collection in Bio-diesel Production Using Visual Basic Interface: Village Bank and Bio-diesel Project. Eng Appl Sci Res [internet]. 2012 May 29 [cited 2026 Aug. 31];37(2):151-9. available from: https://ph01.tci-thaijo.org/index.php/easr/article/view/1700