@InProceedings{Petrov-Klein:2007:Inference,
  title     = {Improved Inference for Unlexicalized Parsing},
  author    = {Slav Petrov and Dan Klein},
  booktitle = {Proceedings of HLT-NAACL},
  month     = {April},
  year      = {2007},
  address   = {Rochester, New York},
  publisher = {Association for Computational Linguistics},
  pages     = {404--411},
  url       = {http://www.aclweb.org/anthology/N/N07/N07-1051},
}