Joint Event Extraction with Hierarchical Policy Network Peixin Huang author Xiang Zhao author Ryuichi Takanobu author Zhen Tan author Weidong Xiao 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 huang-etal-2020-joint 10.18653/v1/2020.coling-main.239 https://aclanthology.org/2020.coling-main.239/ 2020-12 2653 2664