F-PATR: Functional Constraints for Unification-Based Grammars Kent Wittenburg author 1993-06 text 31st Annual Meeting of the Association for Computational Linguistics Association for Computational Linguistics Columbus, Ohio, USA conference publication wittenburg-1993-f 10.3115/981574.981603 https://aclanthology.org/P93-1029/ 1993-06 216 223