[1] Univ Fribourg, Bd Perolles 90, CH-1700 Fribourg, Switzerland
[2] Univ Bayreuth, Univ Str 30, D-95447 Bayreuth, Germany
[3] Univ Lucerne, IWP Inst Swiss Econ Policy, Obergrundstr 9, CH-6003 Luzern, Switzerland
[4] Ctr Res Econ Management & Arts, Zurich, Switzerland