Alcázar, Vidal, Pat Riddle, and Mike Barley. “A Unifying View on Individual Bounds and Heuristic Inaccuracies in Bidirectional Search”. Proceedings of the AAAI Conference on Artificial Intelligence 34, no. 03 (April 3, 2020): 2327-2334. Accessed August 12, 2022. https://ojs.aaai.org/index.php/AAAI/article/view/5611.