Professor of Business taxation at the Free University BerlinVitae:Studies of Management at the Free University Berlin, at the Université de Nice and at the University of Hamburg. 1992-1996: Research Assistant at the Free University Berlin; doctoral thesis on the subject of tax evasion. 1996-2001: Assistant Professor at the European University Viadrina at Frankfurt/Oder; habilitation on Business related expenses versus personal related expenses with regard to income tax bases. 2001-2004: Chair of business taxation at the Ruhr University Bochum. Since 2004: Professor of Business taxation at the Free University Berlin.