BRIEF OHNE UMSCHLAG Friese, Walther Author: Friese, Walther Recipient: Haeckel, Ernst Dating: 11.04.1918
BRIEF [O.A.] Kaspar-Kasparek, H... Author: Kaspar-Kasparek, H... Recipient: Haeckel, Ernst Dating: 25.03.1918
BRIEF OHNE UMSCHLAG Nebuschka, Marie Luise Author: Nebuschka, Marie Luise Recipient: Haeckel, Ernst Dating: 12.02.1918
BRIEF OHNE UMSCHLAG Bülow, Paula von Author: Bülow, Paula von Recipient: Haeckel, Ernst Dating: 09.01.1918
BRIEF OHNE UMSCHLAG Bülow, Paula von Author: Bülow, Paula von Recipient: Haeckel, Ernst Dating: 05.01.1918