"he men working on his behalf were: ...; Dr. Hentzen, curator at the Gem\u00E4ldegalerie, the National Museums; Dr. Kiels von Holst, a scientific researcher at the Staatlichen Museen, Berlin; Dr. Hans Bammann from Dusseldorf who worked as a purchasing agent in France for Museums in Dusseldorf , Cologne, Aachen and Bonn;"@en . . . . . . .