BRIEF [O.A.] Balestra, Juan; Soto, José C. Author: Balestra, Juan; Soto, José C. Recipient: Haeckel, Ernst Corporation: Comité Nacional del Libre Pensamiento Dating: 15.06.1906
BRIEF [O.A.] Bleek, Hermann Author: Bleek, Hermann Recipient: Haeckel, Ernst Corporation: Bleek, Clason & Cia. Dating: 30.10.1914
BRIEF [O.A.] Castex, Susana Torres de Author: Castex, Susana Torres de Recipient: Haeckel, Ernst Dating: 06.04.1903
BRIEF [O.A.] Byron, Julian M... Author: Byron, Julian M... Recipient: Haeckel, Ernst Dating: 07.06.1906
DOKUMENT Burmeister, Hermann Author: Burmeister, Hermann Recipient: Haeckel, Ernst Dating: 20.02.1858
BRIEF [O.A.] Cortines, Luis M... Author: Cortines, Luis M... Recipient: Haeckel, Ernst Dating: 05.11.1906
POSTKARTE Hopcevic, Spiridion jun. Author: Hopcevic, Spiridion jun. Recipient: Haeckel, Ernst Dating: 11.03.1907