Bonet, Blai, and Menkes van den Briel. “Flow-Based Heuristics for Optimal Planning: Landmarks and Merges”. Proceedings of the International Conference on Automated Planning and Scheduling 24, no. 1 (May 10, 2014): 47–55. Accessed May 26, 2026. https://ojs.aaai.org/index.php/ICAPS/article/view/13643.