BRIEF [O.A.] Friedrich, Josephine Author: Friedrich, Josephine Recipient: Haeckel, Ernst Dating: 13.05.1876
BRIEF [O.A.] Friedrich, Josephine Author: Friedrich, Josephine Recipient: Haeckel, Ernst Dating: 19.03.1876
BRIEF [O.A.] Eichel Streiber, Jul... v. Author: Eichel Streiber, Jul... v. Recipient: Haeckel, Ernst Dating: 10.02.1876