@inproceedings{fong-1990-free,
    title = "Free Indexation: Combinatorial Analysis and A Compositional Algorithm",
    author = "Fong, Sandiway",
    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://preview.aclanthology.org/fix-sig-urls/P90-1014/",
    doi = "10.3115/981823.981837",
    pages = "105--110"
}