ANSICHTSKARTE Haeckel, Ernst Author: Haeckel, Ernst Recipient: Delle Grazie, Marie Eugenie Dating: 30.12.1896
ANSICHTSKARTE Haeckel, Ernst Author: Haeckel, Ernst Recipient: Focke, Wilhelm Olbers Dating: 15.06.1916
ANSICHTSKARTE Haeckel, Ernst Author: Haeckel, Ernst Recipient: Carneri, Bartholomäus von Dating: 05.01.1898