Semi-Supervised Semantic Role Labeling via Structural Alignment Hagen Fürstenau author Mirella Lapata author 2012-03 text journal article Computational Linguistics continuing MIT Press Cambridge, MA periodical academic journal furstenau-lapata-2012-semi 10.1162/COLI_a_00087 https://aclanthology.org/J12-1005/ 2012-03 38 1 135 171