Reflections on the Penn Discourse TreeBank, Comparable Corpora, and Complementary Annotation Rashmi Prasad author Bonnie Webber author Aravind Joshi author 2014-12 text journal article Computational Linguistics continuing MIT Press Cambridge, MA periodical academic journal prasad-etal-2014-reflections 10.1162/COLI_a_00204 https://aclanthology.org/J14-4007/ 2014-12 40 4 921 950