Quasi-Destructive Graph Unification Hideto Tomabechi author 1991-06 text 29th Annual Meeting of the Association for Computational Linguistics Association for Computational Linguistics Berkeley, California, USA conference publication tomabechi-1991-quasi-destructive 10.3115/981344.981385 https://aclanthology.org/P91-1041/ 1991-06 315 322