1. Department of Social and Economic Geography, Uppsala University, PO Box 513, S-751 20 Uppsala, Sweden
2. Danish Research Unit for Industrial Dynamics (DRUID), Department of Industrial Economics and Strategy (IVS), Copenhagen Business School (CBS), Howitzvej 60, DK-2000 Frederiksberg C, Denmark and Centre for Economic and Business Research (CEBR), Langelinie Allé 17, DK-2100 Copenhagen, Denmark