1. Gamification Group, Faculty of Information Technology and Communication Sciences, Tampere University, Tampere, Finland
2. Institute of Mathematics and Computer Science, University of São Paulo, São Carlos, São Paulo, Brazil
3. Department of Information Systems, Faculty of Information Technology, Brno University of Technology, Brno, Czech Republic
4. Department of Computer Science, Durham University, Durham, UK
5. São Paulo State College of Technology, Matão, Brazil
6. Harvard Graduate School of Education, Cambridge, United States