Memory-Efficient and Thread-Safe Quasi-Destructive Graph Unification Marcel P van Lohuizen author 2000-10 text Proceedings of the 38th Annual Meeting of the Association for Computational Linguistics Association for Computational Linguistics Hong Kong conference publication van-lohuizen-2000-memory 10.3115/1075218.1075263 https://aclanthology.org/P00-1045/ 2000-10 352 359