Eckerle, J., Chen, J., Sturtevant, N., Zilles, S., & Holte, R. (2017). Sufficient Conditions for Node Expansion in Bidirectional Heuristic Search. Proceedings of the International Conference on Automated Planning and Scheduling, 27(1), 79-87. https://doi.org/10.1609/icaps.v27i1.13825