BRIEF [O.A.] Smither-Jackson, J... H... Author: Smither-Jackson, J... H... Recipient: Haeckel, Ernst Dating: 03.03.1908
BRIEF [O.A.] Haeckel, Henry Author: Haeckel, Henry Recipient: Haeckel, Ernst Corporation: New York Letter Carriers' Association Dating: 19.09.1908
BRIEF OHNE UMSCHLAG Osborn, Henry Fairfield Author: Osborn, Henry Fairfield Recipient: Haeckel, Ernst Corporation: American Museum of Natural History Dating: 12.08.1908
TELEGRAMM Lilienthal, Familie Author: Lilienthal, Familie Recipient: Haeckel, Ernst Dating: 16.02.1908