American Foreign Law Association. German American Law Association.
Secretary, United Nations Commission on International Trade Law & Chief, International Trade Law Branch, Office(s) of Legal Affairs, United Nations Office at Vienna since 1991. Senior Legal Officer, 1985-1991, Legal Officer, 1975-1985, International Trade Law Branch, Office of Legal Affairs, United Nations, Vienna & New York. Lecturer in Law, University of Vienna, since 1985, University of Cologne, 1970-1974.
Rch Assistant, Institute for International and Foreign Private Law, University of Cologne, 1973-1975.