PREFER: Using a Graph-Based Approach to Generate Paraphrases for Language Learning Mei-Hua Chen author Shi-Ting Huang author Chung-Chi Huang author Hsien-Chin Liou author Jason S Chang author 2012-06 text Proceedings of the Seventh Workshop on Building Educational Applications Using NLP Joel Tetreault editor Jill Burstein editor Claudia Leacock editor Association for Computational Linguistics Montréal, Canada conference publication chen-etal-2012-prefer https://aclanthology.org/W12-2009/ 2012-06 80 85