PORTRÄTPOSTKARTE Haeckel, Ernst Author: Haeckel, Ernst Recipient: Bose, Ernst; Koppel, Emil Dating: 15.04.1908
PORTRÄTPOSTKARTE Haeckel, Ernst Author: Haeckel, Ernst Recipient: Arrhenius, Svante Dating: 16.03.1908
PORTRÄTPOSTKARTE Haeckel, Ernst Author: Haeckel, Ernst Recipient: Fürbringer, Hermann Dating: 27.10.1908
PORTRÄTPOSTKARTE Haeckel, Ernst Author: Haeckel, Ernst Recipient: Spann, Alexander Dating: 12.03.1908