BRIEF OHNE UMSCHLAG Haeckel, Heinrich Author: Haeckel, Heinrich Recipient: Haeckel, Ernst Dating: 06.10.1896
BRIEF [O.A.] Haeckel, Heinrich Author: Haeckel, Heinrich Recipient: Haeckel, Ernst Dating: 30.03.1910
BRIEF OHNE UMSCHLAG Haeckel, Heinrich Author: Haeckel, Heinrich Recipient: Haeckel, Ernst Dating: 09.10.1899
BRIEF OHNE UMSCHLAG Haeckel, Heinrich Author: Haeckel, Heinrich Recipient: Haeckel, Ernst Dating: 06.03.1891
BRIEF OHNE UMSCHLAG Haeckel, Heinrich Author: Haeckel, Heinrich Recipient: Haeckel, Ernst Dating: 19.09.1898