@inproceedings{grimes-1978-topic-levels,
    title = "Topic Levels",
    author = "Grimes, Joseph E.",
    editor = "Waltz, David L.",
    booktitle = "Theoretical Issues in Natural Language Processing-2",
    year = "1978",
    url = "https://preview.aclanthology.org/jlcl-multiple-ingestion/T78-1014/"
}