BRIEF OHNE UMSCHLAG Haeckel, Ernst Author: Haeckel, Ernst Recipient: Bölsche, Wilhelm Dating: 06.01.1906
BRIEF OHNE UMSCHLAG Haeckel, Ernst Author: Haeckel, Ernst Recipient: Bölsche, Wilhelm Dating: 05.03.1906
BRIEF OHNE UMSCHLAG Haeckel, Ernst Author: Haeckel, Ernst Recipient: Bölsche, Wilhelm Dating: 01.05.1906
BRIEF OHNE UMSCHLAG Haeckel, Ernst Author: Haeckel, Ernst Recipient: Bölsche, Wilhelm Dating: 11.05.1906