POSTKARTE Osborn, Henry Fairfield Author: Osborn, Henry Fairfield Recipient: Haeckel, Ernst Dating: ??.??.1906
BRIEF [O.A.] Haeckel, Henry Author: Haeckel, Henry Recipient: Haeckel, Ernst Corporation: New York Letter Carriers' Association Dating: 19.09.1908
BRIEF [O.A.] Harper Author: Harper Recipient: Haeckel, Ernst Corporation: Harper & Brothers Publishers Dating: 18.12.1901
BRIEF [O.A.] Harper Author: Harper Recipient: Haeckel, Ernst Corporation: Harper & Brothers Publishers Dating: 09.03.1905
BRIEF [O.A.] Hartmann, S... E... Author: Hartmann, S... E... Recipient: Haeckel, Ernst Dating: 01.02.1914
BRIEF [O.A.] Harvey, W... H... Author: Harvey, W... H... Recipient: Haeckel, Ernst Corporation: Thomas Paine National Historical Association Dating: 13.04.1914
BRIEF [O.A.] Harvey, W... H... Author: Harvey, W... H... Recipient: Haeckel, Ernst Corporation: Thomas Paine National Historical Association Dating: 24.04.1914
