First Author:   Ralf Dewenter Helmut-Schmidt-University Hamburg dewenter@hsu-hh.de   Holstenhofweg 85 Hamburg, 22043, Germany       Second Author: Ulrich Heimeshoff Heinrich-Heine-University of Duesseldorf heimeshoff@dice.hhu.de   Duesseldorf, 40225, Germany       Third Author: Tobias Thomas Media Tenor International thomas@mediatenor.com         http://