Intakarn, J. . “Developing a Freight Routing Model of SMEs Using VRP Solver Program in Sai Mai District, Bangkok”. Journal of Humanities and Social Sciences Thonburi University, vol. 17, no. 1, Dec. 2022, pp. 121-34, https://so03.tci-thaijo.org/index.php/trujournal/article/view/261843.