BRIEF OHNE UMSCHLAG Gandtner, Otto Author: Gandtner, Otto Recipient: Haeckel, Ernst Dating: ??.??.1864
BRIEF [O.A.] Klunzinger, Carl Benjamin Author: Klunzinger, Carl Benjamin Recipient: Haeckel, Ernst Dating: ??.10.1864
BRIEF OHNE UMSCHLAG Rohrbach, Carl Author: Rohrbach, Carl Recipient: Haeckel, Ernst Dating: 24.02.1864