Compacting the Penn Treebank Grammar Alexander Krotov author Mark Hepple author Robert Gaizauskas author Yorick Wilks author 1998-08 text 36th Annual Meeting of the Association for Computational Linguistics and 17th International Conference on Computational Linguistics, Volume 1 Association for Computational Linguistics Montreal, Quebec, Canada conference publication krotov-etal-1998-compacting-penn 10.3115/980845.980962 https://aclanthology.org/P98-1115/ 1998-08 699 703