WIA GC/1887/10 | Ruben, Paul to Warburg, Aby 15/10/1887 | mentions Ernst Levy, Wilhelm Kiesselbach, John [Johann Nicolaus] Hertz, Johannes [Hans] Nippen... |
WIA GC/1887/9 | Ruben, Paul to Warburg, Aby 06/10/1887 | on his life and his thoughts on student fraternities ['Bonna Berolina'? cf. 22/11/1928]; he wants... |
WIA GC/1906/675 | Sieveking, Georg Hermann to Warburg, Aby 14/11/1906 | thanks him for the essay of the Flemish tapestries; as he is researching milk containers he asks... |
WIA GC/1906/676 | Sieveking, Johannes to Warburg, Aby 08/01/1906 | forwards a photograph of a relief |
WIA GC/1906/677 | Warburg, Aby to Sieveking, Johannes 21/01/1906 | postal order for registered mail |