Level-Up: Learning to Improve Proficiency Level of Essays Wen-Bin Han author Jhih-Jie Chen author Chingyu Yang author Jason Chang author 2019-07 text Proceedings of the 57th Annual Meeting of the Association for Computational Linguistics: System Demonstrations Marta R Costa-jussà editor Enrique Alfonseca editor Association for Computational Linguistics Florence, Italy conference publication han-etal-2019-level 10.18653/v1/P19-3033 https://aclanthology.org/P19-3033/ 2019-07 207 212