BRIEF [O.A.] Dallmann, Friedrich Author: Dallmann, Friedrich Recipient: Haeckel, Ernst Dating: 15.02.1904
BRIEF [O.A.] Vorpahl, Katharina Author: Vorpahl, Katharina Recipient: Haeckel, Ernst Dating: 15.02.1904
BRIEF [O.A.] Vogtherr, Ewald Author: Vogtherr, Ewald Recipient: Haeckel, Ernst Corporation: Bund freier religiöser Gemeinden Deutschlands Dating: 18.12.1904
BRIEF [O.A.] Haeckel, Heinrich Author: Haeckel, Heinrich Recipient: Haeckel, Ernst Dating: 12.09.1904
BRIEF [O.A.] Haeckel, Heinrich Author: Haeckel, Heinrich Recipient: Haeckel, Ernst Dating: 19.10.1904
BRIEF [O.A.] Haeckel, Heinrich Author: Haeckel, Heinrich Recipient: Haeckel, Ernst Dating: 15.06.1904