Phrase-Based Query Degradation Modeling for Vocabulary-Independent Ranked Utterance Retrieval J Scott Olsson author Douglas W Oard author 2009-06 text Proceedings of Human Language Technologies: The 2009 Annual Conference of the North American Chapter of the Association for Computational Linguistics Mari Ostendorf editor Michael Collins editor Shri Narayanan editor Douglas W Oard editor Lucy Vanderwende editor Association for Computational Linguistics Boulder, Colorado conference publication olsson-oard-2009-phrase https://aclanthology.org/N09-1021/ 2009-06 182 190