POSTKARTE Erdmann, Gustav Adolf Author: Erdmann, Gustav Adolf Recipient: Haeckel, Ernst Dating: 04.02.1890
POSTKARTE Erdmann, Gustav Adolf Author: Erdmann, Gustav Adolf Recipient: Haeckel, Ernst Dating: 15.05.1892
POSTKARTE Erdmann, Gustav Adolf Author: Erdmann, Gustav Adolf Recipient: Haeckel, Ernst Dating: 24.04.1893
POSTKARTE Erdmann, Gustav Adolf Author: Erdmann, Gustav Adolf Recipient: Haeckel, Ernst Dating: 30.10.1895
POSTKARTE Erdmann, Gustav Adolf Author: Erdmann, Gustav Adolf Recipient: Haeckel, Ernst Dating: 08.10.1899
POSTKARTE Erdmann, Gustav Adolf Author: Erdmann, Gustav Adolf Recipient: Haeckel, Ernst Dating: 03.07.1905