Improving Commonsense Question Answering by Graph-based Iterative Retrieval over Multiple Knowledge Sources Qianglong Chen author Feng Ji author Haiqing Chen author Yin Zhang author 2020-12 text Proceedings of the 28th International Conference on Computational Linguistics Donia Scott editor Nuria Bel editor Chengqing Zong editor International Committee on Computational Linguistics Barcelona, Spain (Online) conference publication chen-etal-2020-improving 10.18653/v1/2020.coling-main.232 https://aclanthology.org/2020.coling-main.232/ 2020-12 2583 2594