BRIEF [O.A.] Arbesser, Cäsar v. Author: Arbesser, Cäsar v. Recipient: Haeckel, Ernst Dating: 08.04.1911
BRIEF [O.A.] Arbesser, Cäsar v. Author: Arbesser, Cäsar v. Recipient: Haeckel, Ernst Dating: 16.04.1911
BRIEF [O.A.] Eurinac, Adolf E... Author: Eurinac, Adolf E... Recipient: Haeckel, Ernst Dating: 18.09.1887
BRIEF [O.A.] Car, Lazar Author: Car, Lazar Recipient: Haeckel, Ernst Corporation: Zoologisches National-Museum Dating: 15.02.1904
BRIEF OHNE UMSCHLAG Marojevic, Bonagracija Author: Marojevic, Bonagracija Recipient: Haeckel, Ernst Dating: 07.07.1871