[1] Department of Computer Science, Bar Ilan University, Ramat Gan, 52900, Israel
[2] Natural Language Processing Group, Microsoft Research, One Microsoft Way, Redmond, WA 98005, United States
[3] Human Language Technologies Research Unit, Fondazione Bruno Kessler, Via Sommarive 18, 38050 Povo - Trento, Italy
[4] Department of Computer Science, University of Illinois at Urbana-Champaign, Urbana-Champaign IL, United States