A Tractable Extension of Linear Indexed Grammars Bill Keller author David Weir author 1995-03 text Seventh Conference of the European Chapter of the Association for Computational Linguistics Steven P Abney editor Erhard W Hinrichs editor Association for Computational Linguistics Dublin, Ireland conference publication keller-weir-1995-tractable https://aclanthology.org/E95-1011/ 1995-03