POSTKARTE Haeckel, Walther Author: Haeckel, Walther Recipient: Haeckel, Ernst; Haeckel, Agnes [Eltern] Dating: 20.09.1896
BILDPOSTKARTE Meyer, Elisabeth Author: Meyer, Elisabeth Recipient: Haeckel, Ernst; Haeckel, Agnes [Eltern] Dating: 04.06.1896
BRIEF [O.A.] Meyer, Elisabeth Author: Meyer, Elisabeth Recipient: Haeckel, Ernst; Haeckel, Agnes [Eltern] Dating: 23.12.1896