Khalifa, A., P. Bontrager, S. Earle, and J. Togelius. “PCGRL: Procedural Content Generation via Reinforcement Learning”. Proceedings of the AAAI Conference on Artificial Intelligence and Interactive Digital Entertainment, vol. 16, no. 1, Oct. 2020, pp. 95-101, https://ojs.aaai.org/index.php/AIIDE/article/view/7416.