PPDB: The Paraphrase Database Juri Ganitkevitch author Benjamin Van Durme author Chris Callison-Burch author 2013-06 text Proceedings of the 2013 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies Lucy Vanderwende editor Hal Daumé III editor Katrin Kirchhoff editor Association for Computational Linguistics Atlanta, Georgia conference publication ganitkevitch-etal-2013-ppdb https://aclanthology.org/N13-1092/ 2013-06 758 764