BRIEF [O.A.] Laube, Natalie von Author: Laube, Natalie von Recipient: Haeckel, Ernst Dating: 06.03.1917
BRIEF [O.A.] Wegner, Julius E... G... Author: Wegner, Julius E... G... Recipient: Haeckel, Ernst Corporation: Julius E. G. Wegner, Verlag Stuttgart Dating: 17.05.1917
BRIEF [O.A.] Wegner, Julius E... G... Author: Wegner, Julius E... G... Recipient: Haeckel, Ernst Corporation: Julius E. G. Wegner, Verlag Stuttgart Dating: 22.11.1917