@inproceedings{heilman-etal-2007-combining,
    title = "Combining Lexical and Grammatical Features to Improve Readability Measures for First and Second Language Texts",
    author = "Heilman, Michael  and
      Collins-Thompson, Kevyn  and
      Callan, Jamie  and
      Eskenazi, Maxine",
    editor = "Sidner, Candace  and
      Schultz, Tanja  and
      Stone, Matthew  and
      Zhai, ChengXiang",
    booktitle = "Human Language Technologies 2007: The Conference of the North {A}merican Chapter of the Association for Computational Linguistics; Proceedings of the Main Conference",
    month = apr,
    year = "2007",
    address = "Rochester, New York",
    publisher = "Association for Computational Linguistics",
    url = "https://aclanthology.org/N07-1058/",
    pages = "460--467"
}