BRIEF [O.A.] Schulze, Franz Eilhard Author: Schulze, Franz Eilhard Recipient: Haeckel, Ernst Dating: 27.11.1917
BRIEF [O.A.] Thoden van Velzen, Syo Kornelius Author: Thoden van Velzen, Syo Kornelius Recipient: Haeckel, Ernst Dating: 28.06.1917
BRIEF [O.A.] Thoden van Velzen, Syo Kornelius Author: Thoden van Velzen, Syo Kornelius Recipient: Haeckel, Ernst Dating: 23.08.1917
BRIEF [O.A.] Schulze, Franz Eilhard Author: Schulze, Franz Eilhard Recipient: Haeckel, Ernst Dating: 20.12.1917