Grenouilleau, F., W.-J. van Hoeve, and J. N. Hooker. “A Multi-Label A* Algorithm for Multi-Agent Pathfinding”. Proceedings of the International Conference on Automated Planning and Scheduling, vol. 29, no. 1, May 2021, pp. 181-5, https://ojs.aaai.org/index.php/ICAPS/article/view/3474.