WIA GC/1907/422 | Warburg, Aby to Koch, Louis [either 13/06/1907 or 14/06/1907] | Dr. [F.?] Wichert pointed Warburg to Koch's collection of rings; asks him whether he has a ring... |
WIA GC/1907/423 | Koch, Louis to Warburg, Aby 16/06/1907 | he does not have rings with the image of Fortuna, as described by Warburg |
WIA GC/1927/512 | Heinitz, Wilhelm to Warburg, Aby 22/06/1927 | reports on the exhibition in Frankfurt am Main, autographs, engravings, prints, partly on the... |