Ungrammaticality and Extra-Grammaticality in Natural Language Understanding Systems Stan C Kwasny author Norman K Sondheimer author 1979-06 text 17th Annual Meeting of the Association for Computational Linguistics Association for Computational Linguistics La Jolla, California, USA conference publication kwasny-sondheimer-1979-ungrammaticality 10.3115/982163.982170 https://aclanthology.org/P79-1006/ 1979-06 19 23