BRIEF OHNE UMSCHLAG Eggeling, Bernhard Author: Eggeling, Bernhard Recipient: Haeckel, Ernst Dating: 22.07.1908
BRIEF OHNE UMSCHLAG Villinger, Arnold Author: Villinger, Arnold Recipient: Haeckel, Ernst Dating: 07.03.1910
BRIEF [O.A.] Harder, I... Author: Harder, I... Recipient: Haeckel, Ernst Corporation: I. Harder, Buch- und Kunsthandlung (Inhaber: H. Funke) Dating: 01.10.1892
BRIEF [O.A.] Roewer, Carl-Friedrich Author: Roewer, Carl-Friedrich Recipient: Haeckel, Ernst Dating: 30.12.1906
BRIEF [O.A.] Lindemann, Arnold Author: Lindemann, Arnold Recipient: Haeckel, Ernst Dating: 18.10.1874