@InProceedings{danescuniculescumizil-lee-ducott:2009:NAACLHLT09,
  author    = {Danescu-Niculescu-Mizil, Cristian  and  Lee, Lillian  and  Ducott, Richard},
  title     = {Without a 'doubt'? Unsupervised Discovery of Downward-Entailing Operators},
  booktitle = {Proceedings of Human Language Technologies: The 2009 Annual Conference of the North American Chapter of the Association for Computational Linguistics},
  month     = {June},
  year      = {2009},
  address   = {Boulder, Colorado},
  publisher = {Association for Computational Linguistics},
  pages     = {137--145},
  url       = {http://www.aclweb.org/anthology/N/N09/N09-1016}
}