First Author:   Joachim Rosenmüller IMW, University of Bielefeld, Germany jr@wiwi.uni-bielefeld.de   University of Bielefeld, Postfach 10 01 31 Bielefeld, 33501, Germany   ++49-521 106 4909(Phone) ++49-521 106 4909(Fax) http://www.wiwi.uni-bielefeld.de/~imw