1. Professor for Sport Economics, Department of Sport Science; Bielefeld University; 33615 Bielefeld Germany
2. Professor for Economics, Faculty of Management, Economics and Social Sciences; University of Cologne; 50923 Cologne Germany
3. Professor for Economics, Department of Managerial Economics; University of Duisburg-Essen; 47057 Duisburg Germany
4. Post-Doc Research Assistant, Department of Managerial Economics; University of Duisburg-Essen; 47057 Duisburg Germany