Clausecker, Robert, and Alexander Reinefeld. “Zero-Aware Pattern Databases With 1-Bit Compression for Sliding Tile Puzzles”. Proceedings of the International Symposium on Combinatorial Search 10, no. 1 (September 1, 2021): 35–43. Accessed May 27, 2026. https://ojs.aaai.org/index.php/SOCS/article/view/18500.