1. Formerly University of Potsdam, Germany; presently ExxonMobil Upstream Research Company, 3319 Mercer Street, Houston, Texas 77027. .
2. University of Potsdam, Applied and Industrial Mathematics, Am Neuen Palais 10, 14469 Potsdam, Germany. .
3. University of Potsdam, Faculty of Geoscience, Karl-Liebnecht-Strasse 24-25, 14414 Postdam, Germany. .