BRIEF [O.A.] Jousset de Bellesme Author: Jousset de Bellesme Recipient: Haeckel, Ernst Dating: 21.01.1910
BRIEF [O.A.] Penninckx, Henry Author: Penninckx, Henry Recipient: Haeckel, Ernst Corporation: Jeunesse Progressiste Dating: 03.08.1910
BRIEF [O.A.] Bellesme, Jousset de Author: Bellesme, Jousset de Recipient: Haeckel, Ernst Dating: 03.12.1910
BRIEF [O.A.] Furnemont, Leo Author: Furnemont, Leo Recipient: Haeckel, Ernst Corporation: Fédération Internationale de la Libre Pensée Dating: 02.07.1910
PORTRÄTPOSTKARTE Friederici, Erna Author: Friederici, Erna Recipient: Haeckel, Ernst Dating: 24.08.1910