BILDPOSTKARTE Sokolowsky, Alexander Author: Sokolowsky, Alexander Recipient: Haeckel, Ernst Dating: 01.01.1907
BILDPOSTKARTE Sokolowsky, Alexander Author: Sokolowsky, Alexander Recipient: Haeckel, Ernst Dating: 12.06.1908
BILDPOSTKARTE Semon, Richard; Semon Maria Author: Semon, Richard; Semon Maria Recipient: Haeckel, Ernst Dating: 04.09.1903
BILDPOSTKARTE Sokolowsky, Alexander Author: Sokolowsky, Alexander Recipient: Haeckel, Ernst Dating: 13.09.1906
BILDPOSTKARTE Sokolowsky, Alexander Author: Sokolowsky, Alexander Recipient: Haeckel, Ernst Dating: 29.07.1907
BILDPOSTKARTE Aigner, Eduard Author: Aigner, Eduard Recipient: Haeckel, Ernst Corporation: Deutscher Monistenbund Dating: 09.09.1913