BRIEF [O.A.] Hempel, Max Author: Hempel, Max Recipient: Haeckel, Ernst Corporation: Bund der Freien Gemeinden und Freidenker-Vereine von Nord-Amerika Dating: 18.06.1904
BRIEF [O.A.] Eldredge, Charles F... Author: Eldredge, Charles F... Recipient: Haeckel, Ernst Corporation: Office of The Philosopher Dating: 14.04.1902
BRIEF [O.A.] Hepner, Adolf Author: Hepner, Adolf Recipient: Haeckel, Ernst Corporation: Abend "Anzeiger", Office of Dating: 27.03.1903
BRIEF [O.A.] Williams, Clarence Author: Williams, Clarence Recipient: Haeckel, Ernst Dating: 30.11.1909
BRIEF [O.A.] Williams, Clarence Author: Williams, Clarence Recipient: Haeckel, Ernst Dating: 25.12.1909
BRIEF [O.A.] Wakeman, Thaddeus Burr Author: Wakeman, Thaddeus Burr Recipient: Haeckel, Ernst Corporation: The Torch of Reason Dating: 06.08.1903