Discourse Relations and Defeasible Knowledge Alex Lascarides author Nicholas Asher author 1991-06 text 29th Annual Meeting of the Association for Computational Linguistics Association for Computational Linguistics Berkeley, California, USA conference publication lascarides-asher-1991-discourse 10.3115/981344.981352 https://aclanthology.org/P91-1008/ 1991-06 55 62