BRIEF [O.A.] Bamberger, Johann Author: Bamberger, Johann Recipient: Haeckel, Ernst Dating: 14.09.1914
BRIEF [O.A.] Aschen, Friedrich von Author: Aschen, Friedrich von Recipient: Haeckel, Ernst Dating: 07.10.1914
BRIEF [O.A.] Baader, Johannes Author: Baader, Johannes Recipient: Haeckel, Ernst Corporation: Verlag der Tagebücher Dating: 31.01.1914
BRIEF [O.A.] Kniesche, Günther Author: Kniesche, Günther Recipient: Haeckel, Ernst Corporation: Zoologischer Garten Dating: 16.03.1914
