Authorized expert for typescripts, printed scripts and documents for the forensic departement of the Landeskriminalamt Baden-Württemberg (Land Office of Criminal Investigation) from 1976 to 2015.
Officially appointed and sworn expert by the Industrie- und Handelskammer Stuttgart (Chamber of Commerce and Industry) since 1988.
Collaboration with the Institut für Schrift- und Urkundenuntersuchung (ISU) e.V. (Scripts and Documents Institute of the University of Mannheim).
Collaboration with the American Society of Questioned Document Examiners.