BRIEF OHNE UMSCHLAG Eggeling, Heinrich von Author: Eggeling, Heinrich von Recipient: Haeckel, Ernst Dating: 25.10.1889
BRIEF [O.A.] Eggeling, Heinrich von Author: Eggeling, Heinrich von Recipient: Haeckel, Ernst Dating: 10.12.1889
BRIEF OHNE UMSCHLAG Ernst [Prinz von Sachsen-Meiningen] Author: Ernst [Prinz von Sachsen-Meiningen] Recipient: Haeckel, Ernst Dating: 03.01.1910
BRIEF [O.A.] Heim, Freiherr von Author: Heim, Freiherr von Recipient: Haeckel, Ernst Dating: 06.12.1899
BRIEF [O.A.] Heim, Freiherr von Author: Heim, Freiherr von Recipient: Haeckel, Ernst Dating: 05.06.1904
BRIEF [O.A.] Schmidt, Reinhold Author: Schmidt, Reinhold Recipient: Haeckel, Ernst Dating: ??.??.1900
BRIEF [O.A.] Schmidt, Reinhold Author: Schmidt, Reinhold Recipient: Haeckel, Ernst Dating: 01.06.1904
BRIEF [O.A.] Schmidt, Reinhold Author: Schmidt, Reinhold Recipient: Haeckel, Ernst Dating: 29.08.1907