Huang, Sen, and Mingyu Xiao. “Object Reachability via Swaps Along a Line”. Proceedings of the AAAI Conference on Artificial Intelligence 33, no. 01 (July 17, 2019): 2037-2044. Accessed April 20, 2024. https://ojs.aaai.org/index.php/AAAI/article/view/4033.