Centering: A Parametric Theory and Its Instantiations Massimo Poesio author Rosemary Stevenson author Barbara Di Eugenio author Janet Hitzeman author 2004 text journal article Computational Linguistics continuing periodical academic journal poesio-etal-2004-centering 10.1162/0891201041850911 https://aclanthology.org/J04-3003/ 2004 30 3 309 363