Rus, Vasile, Sidney D’Mello, Xiangen Hu, and Arthur Graesser. “Recent Advances in Conversational Intelligent Tutoring Systems”. AI Magazine 34, no. 3 (September 15, 2013): 42-54. Accessed September 20, 2021. https://ojs.aaai.org/index.php/aimagazine/article/view/2485.