Gradient-guided Unsupervised Lexically Constrained Text Generation Lei Sha author 2020-11 text Proceedings of the 2020 Conference on Empirical Methods in Natural Language Processing (EMNLP) Bonnie Webber editor Trevor Cohn editor Yulan He editor Yang Liu editor Association for Computational Linguistics Online conference publication sha-2020-gradient 10.18653/v1/2020.emnlp-main.701 https://aclanthology.org/2020.emnlp-main.701/ 2020-11 8692 8703