Universal Discourse Representation Structure Parsing Jiangming Liu author Shay B Cohen author Mirella Lapata author Johan Bos author 2021-06 text journal article Computational Linguistics continuing MIT Press Cambridge, MA periodical academic journal liu-etal-2021-universal 10.1162/coli_a_00406 https://aclanthology.org/2021.cl-2.15/ 2021-06 47 2 445 476