BRIEF [O.A.] Fischbach, Friedr... Author: Fischbach, Friedr... Recipient: Haeckel, Ernst Dating: 25.12.1903
BRIEF [O.A.] Schierenberg, E... Author: Schierenberg, E... Recipient: Haeckel, Ernst Dating: 20.07.1903
BRIEF [O.A.] Lengefeld, Wilhelm Kleinschmidt von Author: Lengefeld, Wilhelm Kleinschmidt von Recipient: Haeckel, Ernst Dating: 09.11.1903
BRIEF [O.A.] Leiningen-Westerburg, K... E... Graf von Author: Leiningen-Westerburg, K... E... Graf von Recipient: Haeckel, Ernst Dating: 24.11.1903
BRIEF [O.A.] Schlier, J... P... Author: Schlier, J... P... Recipient: Haeckel, Ernst Dating: 01.06.1903