ANSICHTSKARTE Haeckel, Walther Author: Haeckel, Walther Recipient: Haeckel, Ernst; Haeckel, Agnes Dating: 02.09.1911
ANSICHTSKARTE Bockelmann, Friedrich Author: Bockelmann, Friedrich Recipient: Haeckel, Ernst Dating: 17.05.1911
ANSICHTSKARTE Haeckel, Ernst; Haeckel, Walther Author: Haeckel, Ernst; Haeckel, Walther Recipient: Haeckel, Agnes Dating: 16.10.1911