BRIEF OHNE UMSCHLAG Bergson, Eduard Author: Bergson, Eduard Recipient: Haeckel, Ernst Dating: 03.10.1875
BRIEF OHNE UMSCHLAG Bergson, Eduard Author: Bergson, Eduard Recipient: Haeckel, Ernst Dating: 30.11.1875
BRIEF OHNE UMSCHLAG Hein, Reinhold Author: Hein, Reinhold Recipient: Haeckel, Ernst Dating: 19.12.1875