BRIEF OHNE UMSCHLAG Radonetz, Eduard Author: Radonetz, Eduard Recipient: Haeckel, Ernst Dating: 01.12.1885
BRIEF [O.A.] Fiedler, Bh... [?] Author: Fiedler, Bh... [?] Recipient: Haeckel, Ernst Dating: 09.04.1878
BRIEF OHNE UMSCHLAG Brettauer, Josef Author: Brettauer, Josef Recipient: Haeckel, Ernst Dating: 03.11.1874