BRIEF OHNE UMSCHLAG Haeckel, Ernst Author: Haeckel, Ernst Recipient: Bölsche, Johanna Dating: 07.03.1914
PORTRÄTPOSTKARTE Haeckel, Ernst Author: Haeckel, Ernst Recipient: Bölsche, Johanna Dating: 24.12.1904
BRIEF OHNE UMSCHLAG Haeckel, Ernst Author: Haeckel, Ernst Recipient: Bölsche, Johanna Dating: 07.03.1908
BRIEF OHNE UMSCHLAG Haeckel, Ernst Author: Haeckel, Ernst Recipient: Bölsche, Johanna Dating: 08.05.1913
BRIEF OHNE UMSCHLAG Haeckel, Ernst Author: Haeckel, Ernst Recipient: Bölsche, Johanna Dating: 31.10.1899