1. Agglomeration and Social Networks Lendület Research Group, Centre for Economic and Regional Studies Hungarian Academy of Sciences Budapest Hungary
2. Laboratory for Networks, Technology and Innovations, Corvinus Institute for Advanced Studies Corvinus University of Budapest Budapest Hungary
3. University of Stavanger Business School Stavanger Norway
4. CRIE, Center of Regional and Innovation Economics University of Bremen Bremen Germany
5. Department of Human Geography and Planning, Faculty of Geosciences Utrecht University Utrecht the Netherlands