@inproceedings{heidorn-1975-augmented,
    title = "Augmented Phrase Structure Grammars",
    author = "Heidorn, George E.",
    editor = "Nash-Webber, B.L.  and
      Schank, Roger",
    booktitle = "Theoretical Issues in Natural Language Processing",
    year = "1975",
    url = "https://preview.aclanthology.org/jlcl-multiple-ingestion/T75-2001/"
}