First Author:   Matthias Hartmann Alfred-Weber-Institute for Economics, University of Heidelberg matthias.hartmann@awi.uni-heidelberg.de   Bergheimer Str. 58 Heidelberg, 69115, Germany   +49 6221 542908(Phone) +49 6221 542908(Fax) Second Author: Helmut Herwartz Department of Econonomics, University of Göttingen hherwartz@uni-goettingen.de   Platz der Göttinger Sieben 5 Göttingen, 37073, Germany   +49 551 - 39 7350(Phone) +49 551 - 39 7279(Fax)