Nguyen, Ngoc Quang, Duc Nghia Nguyen, and Khanh Phuong Nguyen. “Two-Echelon Multi-Trip Multi-Traffic Pickup and Delivery Problem With Time Windows and Synchronization”. JST: Smart Systems and Devices 31, no. 1 (May 15, 2021): 25–32. Accessed June 18, 2025. https://jst.vn/index.php/ssad/article/view/92.