@inproceedings{zhu-etal-2011-indexing,
    title = "Indexing Spoken Documents with Hierarchical Semantic Structures: Semantic Tree-to-string Alignment Models",
    author = "Zhu, Xiaodan  and
      Cherry, Colin  and
      Penn, Gerald",
    editor = "Wang, Haifeng  and
      Yarowsky, David",
    booktitle = "Proceedings of 5th International Joint Conference on Natural Language Processing",
    month = nov,
    year = "2011",
    address = "Chiang Mai, Thailand",
    publisher = "Asian Federation of Natural Language Processing",
    url = "https://preview.aclanthology.org/fix-sig-urls/I11-1057/",
    pages = "509--517"
}