D-Theory: Talking about Talking about Trees Mitchell P Marcus author Donald Hindle author Margaret M Fleck author 1983-06 text 21st Annual Meeting of the Association for Computational Linguistics Association for Computational Linguistics Cambridge, Massachusetts, USA conference publication marcus-etal-1983-theory 10.3115/981311.981337 https://aclanthology.org/P83-1020/ 1983-06 129 136