1. Institute of Political Science, Leiden University, Leiden, The Netherlands
2. Documentation Centre Dutch Political Parties, Groningen University, Groningen, The Netherlands
3. School of Business and Economics, Ethics, Governance and Society, Groningen University, Vrije Universiteit Amsterdam, The Netherlands
4. Le Centre d'étude de la vie politique (CEVIPOL), Université Libre de Bruxelles, Belgium
5. Research Group GASPAR, Ghent University, Belgium