Picking Reference Events from Tense A Formal, Implement able Theory of English Tense-Aspect Semantics Trees: Lenhart K Schubert author Chung Hee Hwang author 1990 text Speech and Natural Language: Proceedings of a Workshop Held at Hidden Valley, Pennsylvania, June 24-27,1990 conference publication schubert-hwang-1990-picking https://aclanthology.org/H90-1008/ 1990