@inproceedings{zifonun-1980-levels,
    title = "Levels of Representation in Natural Language Based Information Systems and Their Relation to the Methodology of Computational Linguistics",
    author = "Zifonun, G.",
    booktitle = "{COLING} 1980 Volume 1: The 8th International Conference on Computational Linguistics",
    year = "1980",
    url = "https://preview.aclanthology.org/fix-sig-urls/C80-1028/"
}