WIA GC/10588 | Warburg, Aby to Warburg, Mary 15/08/1905 | thanks her for photographs of their children; she showed them to Mr. [Henri] and Mrs. Hymans... |
WIA GC/10858 | Warburg, Aby to Schermann, Lucian 01/04/1908 | regrets not having met him at Dr. Julius Derenberg's, his brother-in-law, in Hamburg; he wanted... |
WIA GC/11537 | Warburg, Aby to Derenberg, Julius 01/02/1912 | replies to Derenberg's letter re appointment in Halle; repeats his reasons why he could not do... |
WIA GC/11815 | Warburg, Aby to Derenberg, Julius 13/03/1913 | angry letter by Warburg because Derenberg has not thanked him for the offprint of his article... |
WIA GC/13250 | Derenberg, Julius to Warburg, Aby 20/03/1921 | congratulates him on the final exams of Marietta and Frede; his own son Carl and his nephew... |