1. Department of Statistical Sciences; University of Bologna; Via Belle Arti 41 Bologna 40126 Italy
2. Center for Advanced Studies in Tourism; Campus of Rimini-University of Bologna
3. Department of Economics, Business and Statistics; University of Palermo; Viale delle Scienze Edificio 13 Palermo 90128 Italy
4. Tinbergen Institute Amsterdam; Gustav Mahlerplein 117; 1082 MS Amsterdam The Netherlands
5. Adam Mickiewicz University