1. Qatar Computing Research Institute, Hamad Bin Khalifa University, Doha, Qatar
2. Turku School of Economics, University of Turku, Turku, Finland
3. Centre for Psychological Research and Social Intervention (CIS), ISCTE-Instituto Universitário de Lisboa, Lisbon, Portugal
4. Computer Science Department, University of Illinois at Urbana-Champaign, Champaign, IL, USA