BRIEF [O.A.] Dory-Ehrenfreund Author: Dory-Ehrenfreund Recipient: Haeckel, Ernst Corporation: Wiener Giro- und Cassen-Verein Dating: 22.02.1908
BRIEF [O.A.] Diehl, Gustav Eugen Author: Diehl, Gustav Eugen Recipient: Haeckel, Ernst Corporation: Erdgeist, Illustrierte Halbmonatsschrift Dating: 05.08.1908
POSTKARTE Obersteiner, Wolfgang Author: Obersteiner, Wolfgang Recipient: Haeckel, Ernst Dating: 15.06.1908
POSTKARTE Obersteiner, Wolfgang Author: Obersteiner, Wolfgang Recipient: Haeckel, Ernst Dating: 12.12.1908
POSTKARTE Pineles, Horatius M... Author: Pineles, Horatius M... Recipient: Haeckel, Ernst Dating: 02.08.1908