1. Department of Mathematical Economics, Wroclaw University of Economics and Business , Komandorska 118/120, 53-345 Wroclaw , Poland
2. Minda de Gunzburg Center for European Studies (CES), Harvard University , Adolphus Busch Hall, 27 Kirkland Street, Cambridge, MA 02138 , USA
3. Department of International Business, Wroclaw University of Economics and Business , Komandorska 118/120, 53-345 Wroclaw , Poland
4. Trinity College, University of Cambridge , Cambridge CB2 1TQ , UK