POSTKARTE Grazie, Marie Eugenie delle Author: Grazie, Marie Eugenie delle Recipient: Haeckel, Ernst Dating: 22.08.1903
BRIEF OHNE UMSCHLAG Lehmann-Russbüldt, Otto Author: Lehmann-Russbüldt, Otto Recipient: Haeckel, Ernst Corporation: Giordano-Bruno-Bund Dating: 02.01.1903
BRIEF OHNE UMSCHLAG Haeckel, Ernst Author: Haeckel, Ernst Recipient: Strasburger, Eduard Dating: 09.12.1903
BILDPOSTKARTE Haeckel, Ernst Author: Haeckel, Ernst Recipient: Verworn, Max; Verworn, Josephine Dating: 29.12.1903
BRIEF OHNE UMSCHLAG Meyer, Hans Author: Meyer, Hans Recipient: Uslar-Gleichen, Frida von Corporation: Bibliographisches Institut Dating: 23.10.1903
OFFENER BRIEF Lagarrigue, Juan Enrique Author: Lagarrigue, Juan Enrique Recipient: Haeckel, Ernst Dating: 12.10.1903
POSTKARTE Grazie, Marie Eugenie delle Author: Grazie, Marie Eugenie delle Recipient: Haeckel, Ernst Dating: 22.08.1903
BRIEF [O.A.] Greenfield, Frederick J... Author: Greenfield, Frederick J... Recipient: Haeckel, Ernst Dating: 22.01.1903