Anurattananon, Chanpen, Prachuab Klomjit, Amnaht Amaluk, Narawadee Keereewan, and Nutchanun Choosombut. “Efficiency Improvement of Customer Service of Delivery Service System by Using Simulation: A Case Study of Sample Delivery Service Company”. Thai Industrial Engineering Network Journal 4, no. 2 (December 31, 2018): 59–69. Accessed May 2, 2024. https://ph02.tci-thaijo.org/index.php/ienj/article/view/176730.