BILDPOSTKARTE Sokolowsky, Alexander Author: Sokolowsky, Alexander Recipient: Haeckel, Ernst Dating: 23.05.1907
BILDPOSTKARTE Sokolowsky, Alexander Author: Sokolowsky, Alexander Recipient: Haeckel, Ernst Dating: 01.01.1907
BILDPOSTKARTE Sokolowsky, Alexander Author: Sokolowsky, Alexander Recipient: Haeckel, Ernst Dating: 29.07.1907
BILDPOSTKARTE Magnussen, Harro; Häberlin, Carl Author: Magnussen, Harro; Häberlin, Carl Recipient: Haeckel, Ernst Dating: 15.06.1907