WIA FC/1897/27/13 | Warburg, Aby to Warburg, Charlotte and Warburg, Moritz 16/03/1897 | apologizes for not coming to Hamburg to celebrate their birthday; he has to give a lecture in... |
WIA FC/1899/12/8 | Warburg, Aby to Warburg, Mary [July 1899] | apologizes for not writing every day; he is very busy with working in the library; he visited the... |
WIA GC/1895/AMERICA/29 | Warburg, Aby to Fewkes, J. Walter 10/10/1896 | apologizes for late reply; upon returning to Europe he had many things to organise; he was not... |
WIA GC/1896/76 | Steinen, Karl von den to Warburg, Aby 23/12/1896 | forwards a letter |
WIA GC/1896/77 | Warburg, Aby to Karl von den Steinen? [December 1896] | on the plan of an expedition to Mexico, co-financed by Germany |