POSTKARTE Haeckel, Ernst Author: Haeckel, Ernst Recipient: Delle Grazie, Marie Eugenie Dating: 29.10.1896
POSTKARTE Reinicke, Emanuel Author: Reinicke, Emanuel Recipient: Haeckel, Ernst Corporation: Wilhelm Engelmann Verlagsbuchhandlung Dating: 29.09.1896
POSTKARTE Breitenbach, Wilhelm Author: Breitenbach, Wilhelm Recipient: Haeckel, Ernst Dating: 15.10.1896