BRIEF [O.A.] Haeckel, Ernst Author: Haeckel, Ernst Recipient: Bleek, Wilhelm Heinrich Immanuel Dating: 15.09.1866
BRIEF [O.A.] Haeckel, Ernst Author: Haeckel, Ernst Recipient: Haeckel, Carl Gottlob Dating: 10.03.1866
BRIEF [O.A.] Haeckel, Charlotte Author: Haeckel, Charlotte Recipient: Haeckel, Ernst Dating: 12.01.1866
BRIEF [O.A.] Haeckel, Charlotte Author: Haeckel, Charlotte Recipient: Haeckel, Ernst Dating: 29.01.1866