Approximating Context-Free Grammars with a Finite-State Calculus Edmund Grimley Evans author 1997-07 text 35th Annual Meeting of the Association for Computational Linguistics and 8th Conference of the European Chapter of the Association for Computational Linguistics Association for Computational Linguistics Madrid, Spain conference publication evans-1997-approximating 10.3115/976909.979675 https://aclanthology.org/P97-1058/ 1997-07 452 459