KARTE Bölsche, Wilhelm; Bölsche, Johanna Author: Bölsche, Wilhelm; Bölsche, Johanna Recipient: Haeckel, Ernst Dating: 24.12.1906
KARTE Bölsche, Wilhelm; Bölsche, Johanna Author: Bölsche, Wilhelm; Bölsche, Johanna Recipient: Haeckel, Ernst Dating: 31.12.1905
KARTE Willkomm-Schneider, Martha Author: Willkomm-Schneider, Martha Recipient: Haeckel, Ernst Dating: 16.02.1914
KARTE Altenburgerin [Pseudonym] Author: Altenburgerin [Pseudonym] Recipient: Haeckel, Ernst Dating: 15.02.1910