1. University of Wuppertal, Germany, Indiana University
2. American University, Norwegian School of Economics, Norway
3. Bergische Universität Wuppertal, Germany, Rheinisch-Westfälisches Institut für Wirtschaftsforschung (RWI), Essen, Germany
4. Trier University, Germany, Utrecht University, The Netherlands
5. Tilburg University, The Netherlands, University of Antwerp, Belgium, Cardiff University, United Kingdom