Botea, Adi, and Vadim Bulitko. “Tiered State Expansion in Optimization Crosswords”. Proceedings of the AAAI Conference on Artificial Intelligence and Interactive Digital Entertainment 18, no. 1 (October 11, 2022): 79-86. Accessed April 20, 2024. https://ojs.aaai.org/index.php/AIIDE/article/view/21950.