BRIEF [O.A.] Krauseneck, Valentine Author: Krauseneck, Valentine Recipient: Haeckel, Ernst Dating: 12.06.1897
BRIEF OHNE UMSCHLAG Krauseneck, Gustav Adolf Author: Krauseneck, Gustav Adolf Recipient: Haeckel, Ernst Dating: 14.09.1897
BRIEF OHNE UMSCHLAG Krauseneck, Pauline, geb. Koepl Author: Krauseneck, Pauline, geb. Koepl Recipient: Haeckel, Ernst Dating: 12.09.1897