[1] ZEW Leibniz Ctr European Econ Res, Dept Econ Innovat & Ind Dynam, Mannheim, Germany
[2] Katholieke Univ Leuven, Dept Econ, Leuven, Belgium
[3] Katholieke Univ Leuven, Dept Management Strategy & Innovat, Leuven, Belgium
[4] Katholieke Univ Leuven, Ctr R&D Monitoring ECOOM, Leuven, Belgium