@InProceedings{zhu-cherry-penn:2011:IJCNLP-2011,
  author    = {Zhu, Xiaodan  and  Cherry, Colin  and  Penn, Gerald},
  title     = {Indexing Spoken Documents with Hierarchical Semantic Structures: Semantic Tree-to-string Alignment Models},
  booktitle = {Proceedings of 5th International Joint Conference on Natural Language Processing},
  month     = {November},
  year      = {2011},
  address   = {Chiang Mai, Thailand},
  publisher = {Asian Federation of Natural Language Processing},
  pages     = {509--517},
  url       = {http://www.aclweb.org/anthology/I11-1057}
}