BRIEF [O.A.] Haeckel, Charlotte Author: Haeckel, Charlotte Recipient: Haeckel, Ernst Dating: 25.04.1876
BRIEF [O.A.] Haeckel, Charlotte Author: Haeckel, Charlotte Recipient: Haeckel, Ernst Dating: 18.07.1881
BRIEF [O.A.] Haeckel, Charlotte Author: Haeckel, Charlotte Recipient: Haeckel, Ernst Dating: 02.02.1870
BRIEF [O.A.] Haeckel, Charlotte Author: Haeckel, Charlotte Recipient: Haeckel, Ernst Dating: ??.06.1884
