BRIEF MIT UMSCHLAG Haeckel, Ernst Author: Haeckel, Ernst Recipient: Delle Grazie, Marie Eugenie Dating: 30.04.1898
BRIEF MIT UMSCHLAG Haeckel, Ernst Author: Haeckel, Ernst Recipient: Delle Grazie, Marie Eugenie Dating: 04.09.1898
POSTKARTE Haeckel, Ernst Author: Haeckel, Ernst Recipient: Sarasin, Paul; Sarasin, Fritz Dating: 16.07.1898
BRIEF [O.A.] Eichholtz, Alfred Author: Eichholtz, Alfred Recipient: Haeckel, Ernst Dating: 15.02.1898
BRIEF [O.A.] Dobeneck, Freiherr von Author: Dobeneck, Freiherr von Recipient: Haeckel, Ernst Dating: 04.11.1898
