BRIEF OHNE UMSCHLAG Bölsche, Wilhelm Author: Bölsche, Wilhelm Recipient: Haeckel, Ernst Dating: 13.06.1912
BRIEF OHNE UMSCHLAG Bernstein, Herman Author: Bernstein, Herman Recipient: Haeckel, Ernst Corporation: The New-York Sun Dating: 16.06.1912
POSTKARTE Rakus, Theodor G... Author: Rakus, Theodor G... Recipient: Haeckel, Ernst Dating: 14.08.1912
BRIEF [O.A.] Schimmelmann, Frh. Hugo von Author: Schimmelmann, Frh. Hugo von Recipient: Haeckel, Ernst Dating: 15.02.1912
BRIEF [O.A.] Linzbauer, Hella von Author: Linzbauer, Hella von Recipient: Haeckel, Ernst Dating: 19.12.1912
BRIEF [O.A.] Ticehurst, J... N... G... Author: Ticehurst, J... N... G... Recipient: Haeckel, Ernst Dating: 09.12.1912
POSTKARTE Schaufenbühl, Friedrich Author: Schaufenbühl, Friedrich Recipient: Haeckel, Ernst Dating: 22.12.1912