POSTKARTE Bölsche, Wilhelm; Bölsche, Johanna [et al.] Author: Bölsche, Wilhelm; Bölsche, Johanna [et al.] Recipient: Haeckel, Ernst Dating: 13.02.1909
BRIEF OHNE UMSCHLAG Altenburgerin [Pseudonym] Author: Altenburgerin [Pseudonym] Recipient: Haeckel, Ernst Dating: 12.10.1909
ANSICHTSKARTE Bölsche, Wilhelm; Bölsche, Johanna Author: Bölsche, Wilhelm; Bölsche, Johanna Recipient: Haeckel, Ernst Dating: 22.12.1909
