Qiu, Minghui, Xinjing Huang, Cen Chen, Feng Ji, Chen Qu, Wei Wei, Jun Huang, and Yin Zhang. 2021. “Reinforced History Backtracking for Conversational Question Answering”. Proceedings of the AAAI Conference on Artificial Intelligence 35 (15):13718-26. https://doi.org/10.1609/aaai.v35i15.17617.