BRIEF OHNE UMSCHLAG Heldburg, Helene Freifrau von Author: Heldburg, Helene Freifrau von Recipient: Haeckel, Agnes Dating: 29.07.1895
BRIEF [O.A.] Brockhaus, Ottilie Author: Brockhaus, Ottilie Recipient: Haeckel, Agnes Dating: ??.??.1889