@inproceedings{johnson-1990-expressing,
    title = "Expressing Disjunctive and Negative Feature Constraints With Classical First-Order Logic.",
    author = "Johnson, Mark",
    booktitle = "28th Annual Meeting of the Association for Computational Linguistics",
    month = jun,
    year = "1990",
    address = "Pittsburgh, Pennsylvania, USA",
    publisher = "Association for Computational Linguistics",
    url = "https://aclanthology.org/P90-1022/",
    doi = "10.3115/981823.981845",
    pages = "173--179"
}