BRIEF [O.A.] Klaucke-Blaurock, Else Author: Klaucke-Blaurock, Else Recipient: Haeckel, Ernst Dating: 21.03.1911
BRIEF [O.A.] Vogtherr, E... Author: Vogtherr, E... Recipient: Haeckel, Ernst Corporation: Deutscher Freidenker-Bund Dating: 01.08.1911
BRIEF [O.A.] Vogtherr, E... Author: Vogtherr, E... Recipient: Haeckel, Ernst Corporation: Deutscher Freidenker-Bund Dating: 19.12.1911
BRIEF [O.A.] Haeckel, Heinrich Author: Haeckel, Heinrich Recipient: Haeckel, Ernst Dating: 28.12.1911
BRIEF [O.A.] Haeckel, Heinrich Author: Haeckel, Heinrich Recipient: Haeckel, Ernst Dating: 27.09.1911
BRIEF [O.A.] Haeckel, Heinrich Author: Haeckel, Heinrich Recipient: Haeckel, Ernst Dating: 04.05.1911
BRIEF [O.A.] Haeckel, Heinrich Author: Haeckel, Heinrich Recipient: Haeckel, Ernst Dating: 30.04.1911