First Author:   Harry Haupt University of Regensburg harald.haupt@wiwi.uni-r.de   Department of Econometrics, University of Regensburg Regensburg, 93040, Germany       http://www.wiwi.uni-regensburg.de/oberhofer/ Second Author: Walter Oberhofer University of Regensburg walter.oberhofer@wiwi.uni-r.de