Discrete Optimization for Unsupervised Sentence Summarization with Word-Level Extraction Raphael Schumann author Lili Mou author Yao Lu author Olga Vechtomova author Katja Markert author 2020-07 text Proceedings of the 58th Annual Meeting of the Association for Computational Linguistics Dan Jurafsky editor Joyce Chai editor Natalie Schluter editor Joel Tetreault editor Association for Computational Linguistics Online conference publication schumann-etal-2020-discrete 10.18653/v1/2020.acl-main.452 https://aclanthology.org/2020.acl-main.452/ 2020-07 5032 5042