Zero subject detection for Polish Mateusz Kopeć author 2014-04 text Proceedings of the 14th Conference of the European Chapter of the Association for Computational Linguistics, volume 2: Short Papers Shuly Wintner editor Stefan Riezler editor Sharon Goldwater editor Association for Computational Linguistics Gothenburg, Sweden conference publication kopec-2014-zero 10.3115/v1/E14-4043 https://aclanthology.org/E14-4043/ 2014-04 221 225