Alford, Ron, Vikas Shivashankar, Ugur Kuter, and Dana Nau. “On the Feasibility of Planning Graph Style Heuristics for HTN Planning”. Proceedings of the International Conference on Automated Planning and Scheduling 24, no. 1 (May 10, 2014): 2-10. Accessed May 5, 2024. https://ojs.aaai.org/index.php/ICAPS/article/view/13630.