Fact-level Extractive Summarization with Hierarchical Graph Mask on BERT Ruifeng Yuan author Zili Wang author Wenjie Li 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 yuan-etal-2020-fact 10.18653/v1/2020.coling-main.493 https://aclanthology.org/2020.coling-main.493/ 2020-12 5629 5639