@inproceedings{pado-2017-question,
    title = "Question Difficulty {--} How to Estimate Without Norming, How to Use for Automated Grading",
    author = "Pad{\'o}, Ulrike",
    editor = "Tetreault, Joel  and
      Burstein, Jill  and
      Leacock, Claudia  and
      Yannakoudakis, Helen",
    booktitle = "Proceedings of the 12th Workshop on Innovative Use of {NLP} for Building Educational Applications",
    month = sep,
    year = "2017",
    address = "Copenhagen, Denmark",
    publisher = "Association for Computational Linguistics",
    url = "https://preview.aclanthology.org/fix-sig-urls/W17-5001/",
    doi = "10.18653/v1/W17-5001",
    pages = "1--10"
}