Geib, Christopher, and Robert Goldman. “Recognizing Plans With Loops Represented in a Lexicalized Grammar”. Proceedings of the AAAI Conference on Artificial Intelligence 25, no. 1 (August 4, 2011): 958-963. Accessed October 2, 2022. https://ojs.aaai.org/index.php/AAAI/article/view/8010.