@inproceedings{chen-etal-2009-improved,
    title = "Improved pronunciation features for construct-driven assessment of non-native spontaneous speech",
    author = "Chen, Lei  and
      Zechner, Klaus  and
      Xi, Xiaoming",
    editor = "Ostendorf, Mari  and
      Collins, Michael  and
      Narayanan, Shri  and
      Oard, Douglas W.  and
      Vanderwende, Lucy",
    booktitle = "Proceedings of Human Language Technologies: The 2009 Annual Conference of the North {A}merican Chapter of the Association for Computational Linguistics",
    month = jun,
    year = "2009",
    address = "Boulder, Colorado",
    publisher = "Association for Computational Linguistics",
    url = "https://aclanthology.org/N09-1050/",
    pages = "442--449"
}