One interesting source of information is: <Salt Mines and Castles> by Thomas Carr Howe, Jr. The Bobbs-Merrill Co., Indianapolis. 1945. Subtitle: The Discovery and Restitution of Looted European Art. There are numerous illustration, as well as an appendix listing paintings transferred from Germany to the National Gallery, and copies of correspondence protesting this action. Jack C. Thompson Thompson Conservation Lab Portland, OR [log in to unmask]