BRIEF OHNE UMSCHLAG Benedikt, Moritz Author: Benedikt, Moritz Recipient: Haeckel, Ernst Dating: 28.01.1918
BRIEF OHNE UMSCHLAG Benedikt, Moritz Author: Benedikt, Moritz Recipient: Haeckel, Ernst Dating: 31.01.1918
BRIEF [O.A.] Bettelheim, Anton Author: Bettelheim, Anton Recipient: Haeckel, Ernst Dating: 19.10.1890
BRIEF OHNE UMSCHLAG Borngräber, Otto Author: Borngräber, Otto Recipient: Haeckel, Ernst Dating: 08.11.1901
BRIEF [O.A.] Bettelheim, Anton Author: Bettelheim, Anton Recipient: Haeckel, Ernst Dating: 14.01.1898
BRIEF [O.A.] Austengruber, F... Author: Austengruber, F... Recipient: Haeckel, Ernst Dating: 02.11.1911