BRIEF OHNE UMSCHLAG Radonetz, Eduard Author: Radonetz, Eduard Recipient: Haeckel, Ernst Dating: 01.12.1885
BRIEF [O.A.] Pascotini, B... Carl Author: Pascotini, B... Carl Recipient: Haeckel, Ernst Dating: 10.01.1873
BRIEF OHNE UMSCHLAG Krauseneck, Gustav Adolf Author: Krauseneck, Gustav Adolf Recipient: Haeckel, Ernst Dating: 12.09.1881
BRIEF OHNE UMSCHLAG Krauseneck, Valentine Author: Krauseneck, Valentine Recipient: Haeckel, Ernst Dating: 31.10.1881
BRIEF OHNE UMSCHLAG Krauseneck, Gustav Adolf Author: Krauseneck, Gustav Adolf Recipient: Haeckel, Ernst Dating: 25.01.1889