WIA GC/10705 | Warburg, Aby to Koetschau, Karl 09/10/1907 | on corrections to be entered into the list of participants at the International Congress of the... |
WIA GC/11089 | Warburg, Aby to Koetschau, Karl; Kautzsch, Rudolf and Wulff, Otto 15/08/1909 | agrees with the others on [Hugo von] Tschudi re Annual Report and Bibliography; discusses who... |