N. A.-M. El-Sherbeny, “Minimum Convex and Differentiable Cost Flow Problem with Time Windows”, IJSBAR, vol. 20, no. 1, pp. 139–150, Jan. 2015, Accessed: Sep. 18, 2025. [Online]. Available: https://gssrr.org/JournalOfBasicAndApplied/article/view/3368