ANSICHTSKARTE Haeckel, Ernst Author: Haeckel, Ernst Recipient: Focke, Wilhelm Olbers Dating: 22.02.1916
ANSICHTSKARTE Haeckel, Ernst Author: Haeckel, Ernst Recipient: Besser, Käthe; Besser, Leopold Dating: 03.01.1903
ANSICHTSKARTE Haeckel, Ernst Author: Haeckel, Ernst Recipient: Schoeller, Caesar, und Frau Dating: 01.01.1918