BRIEF [O.A.] Wollenmann, A... G... Author: Wollenmann, A... G... Recipient: Haeckel, Ernst Dating: 20.08.1901
BRIEF [O.A.] Dünweg, Oskar Author: Dünweg, Oskar Recipient: Haeckel, Ernst Corporation: Oskar Duenweg, Leather and Findings Dating: 14.11.1906
BRIEF [O.A.] Franklin, Charles Kendall Author: Franklin, Charles Kendall Recipient: Haeckel, Ernst Corporation: Schultz and Hulett Block Dating: 16.03.1905
BRIEF [O.A.] Bowles, T... J... Author: Bowles, T... J... Recipient: Haeckel, Ernst Corporation: Free Thought Science Reason VS. Superstition Dating: 27.09.1906
BRIEF [O.A.] Bowles, T... J... Author: Bowles, T... J... Recipient: Haeckel, Ernst Corporation: National Rationalist Association Dating: 02.12.1914