BRIEF OHNE UMSCHLAG Sethe, Hermine Author: Sethe, Hermine Recipient: Haeckel, Ernst Dating: 22.02.1864
BRIEF [O.A.] Sethe, Wilhelmine (geb. Bölling) Author: Sethe, Wilhelmine (geb. Bölling) Recipient: Haeckel, Ernst Dating: 21.12.1864
BRIEF OHNE UMSCHLAG Gandtner, Otto Author: Gandtner, Otto Recipient: Haeckel, Ernst Dating: ??.??.1864
BRIEF [O.A.] Richter, Ferdinand Author: Richter, Ferdinand Recipient: Haeckel, Ernst Dating: 19.02.1864