BRIEF [O.A.] Lowie, Robert H... Author: Lowie, Robert H... Recipient: Haeckel, Ernst Dating: 16.12.1903
BRIEF [O.A.] Loeb, Jacques Author: Loeb, Jacques Recipient: Haeckel, Ernst Corporation: The Rockefeller Institute for Medical Research Dating: 22.05.1912
BRIEF OHNE UMSCHLAG Loeb, Jacques Author: Loeb, Jacques Recipient: Haeckel, Ernst Corporation: The Rockefeller Institute for Medical Research Dating: 15.12.1911
BRIEF [O.A.] Kahrs, Hans Author: Kahrs, Hans Recipient: Haeckel, Ernst Corporation: Monopol Import/Export Union Inc. Dating: 05.06.1914
