Name Perplexity Octavian Popescu author 2009-06 text Proceedings of Human Language Technologies: The 2009 Annual Conference of the North American Chapter of the Association for Computational Linguistics, Companion Volume: Short Papers Mari Ostendorf editor Michael Collins editor Shri Narayanan editor Douglas W Oard editor Lucy Vanderwende editor Association for Computational Linguistics Boulder, Colorado conference publication popescu-2009-name https://aclanthology.org/N09-2039/ 2009-06 153 156