BRIEF [O.A.] Herzfeld, Hugo Author: Herzfeld, Hugo Recipient: Haeckel, Ernst Corporation: Herzfeld Hnos. Almacen Internacional Dating: 24.10.1908
BRIEF [O.A.] Rassmann, Otto Author: Rassmann, Otto Recipient: Haeckel, Ernst Corporation: Buch-, Antiquariats- und Musikalienhandlung Dating: 10.12.1908
BRIEF [O.A.] Vigano, Ernestina Dello Author: Vigano, Ernestina Dello Recipient: Haeckel, Ernst Dating: 16.12.1908
BRIEF [O.A.] Ticehurst, J... N... G... Author: Ticehurst, J... N... G... Recipient: Haeckel, Ernst Dating: 19.08.1908