1. GESIS--Leibniz Institute for the Social Sciences, Germany and Graz University of Technology, Graz, Austria
2. GESIS--Leibniz Institute for the Social Sciences, Cologne, Germany
3. GESIS--Leibniz Institute for the Social Sciences, Mannheim, Germany
4. University of Applied Labour Studies, Mannheim, Germany
5. RWTH Aachen University, Germany and GESIS -- Leibniz Institute for the Social Sciences, Cologne, Germany