1. Department of Finance and Statistics, Swedish School of Economics and Business Administration, PO Box 479, FIN-00101 Helsinki, Finland
2. Department of Economics, Umeå University, SE-901 87 Umeå, Sweden
3. Department of Economics, Dalarna University, SE-781 88 Borlänge, Sweden
4. The Swedish Retail Institute (HUI), SE-103 29 Stockholm, Sweden