Yu, Hong, and Tyler Trawick. “Personalized Procedural Content Generation to Minimize Frustration and Boredom Based on Ranking Algorithm”. Proceedings of the AAAI Conference on Artificial Intelligence and Interactive Digital Entertainment 7, no. 1 (October 9, 2011): 208–213. Accessed May 28, 2026. https://ojs.aaai.org/index.php/AIIDE/article/view/12442.