[1] Ctr European Econ Res ZEW, Dept Ind Econ & Int Management, D-68034 Mannheim, Germany
[2] Univ Hamburg, Inst Marketing & Media, Dept Marketing & Innovat, D-20146 Hamburg, Germany
[3] Max Planck Inst Econ, Entrepreneurship Growth & Publ Policy Grp, D-07745 Jena, Germany
[4] Univ Augsburg, Dept Econ & Business, Chair Management & Org, D-86159 Augsburg, Germany