1. Department of Economics and Law, HTW Berlin University of Applied Sciences, Berlin, Germany
2. Institute of Psychology, Humboldt University, Berlin, Germany
3. Centre for Sociological Research, LUCAS – KU Leuven, Belgium
4. Department of General Practice and Elderly Care Medicine, VU Amsterdam, Amsterdam, Netherlands
5. Medical School, Università Cattolica del Sacro Cuore, Milan, Italy
6. Department of Geriatrics, Landspitali University Hospital, University of Iceland, Reykjavík, Iceland