WIA GC 1931/2797 | Sieveking, Heinrich to Bing, Gertrud 14/05/1931 | |
WIA GC 1931/2798 | Bing, Gertrud to Sieveking, Heinrich 12/08/1931 | |
WIA GC 1931/2799 | Bing, Gertrud to Sieveking, Heinrich [August 1931] | |
WIA GC 1931/2800 | Sieveking, Heinrich to Bing, Gertrud 03/09/1931 | |
WIA GC 1931/2801 | Sieveking, Heinrich to Bing, Gertrud 26/11/1931 | |