KARTE Focke, Wilhelm Olbers Author: Focke, Wilhelm Olbers Recipient: Haeckel, Ernst Dating: 22.05.1911
KARTE Huschke, Otto; Huschke, Klotilde Author: Huschke, Otto; Huschke, Klotilde Recipient: Haeckel, Ernst Dating: 04.03.1911
KARTE Waldeyer-Hartz, Wilhelm von Author: Waldeyer-Hartz, Wilhelm von Recipient: Haeckel, Ernst Dating: 08.08.1911
KARTE Magnus Witwe, Otto; Magnus, Walter Author: Magnus Witwe, Otto; Magnus, Walter Recipient: Haeckel, Ernst Dating: 29.04.1911
KARTE [Gruyter, Walter de] Author: [Gruyter, Walter de] Recipient: Haeckel, Ernst Corporation: Verlagsbuchhandlung Georg Reimer in Berlin Dating: 15.08.1911