BRIEF OHNE UMSCHLAG Haeckel, Ernst Author: Haeckel, Ernst Recipient: Haeckel, Charlotte Dating: 13.04.1873
BRIEF [O.A.] Georgionpoulos, S... Author: Georgionpoulos, S... Recipient: Haeckel, Ernst Dating: 10.11.1906
BRIEF [O.A.] Cogevina, Nicolaus Author: Cogevina, Nicolaus Recipient: Haeckel, Ernst Dating: 23.08.1877
BRIEF [O.A.] Cogevina, Nicolaus Author: Cogevina, Nicolaus Recipient: Haeckel, Ernst Dating: 17.09.1877
BRIEF [O.A.] Délyanny, Théodore Author: Délyanny, Théodore Recipient: Haeckel, Ernst Dating: 21.06.1896
