1. Faculty of Informatics; Università della Svizzera italiana; Via Giuseppe Buffi 13 CH-6904 Lugano Switzerland
2. IBM Watson Research Center; PO Box 218 Yorktown Heights NY 10598 USA
3. Department of Computer Engineering; Bilkent University; Bilkent Ankara 06800 Turkey
4. Department of Computer Science; New York University; 715 Broadway Room 711 New York NY 10003 USA