BRIEF [O.A.] Ulrich, Carl Author: Ulrich, Carl Recipient: Haeckel, Ernst Corporation: Französischer Hof Dating: 16.08.1905
BRIEF [O.A.] Weinland, David Friedrich Author: Weinland, David Friedrich Recipient: Haeckel, Ernst Dating: 18.03.1888
BRIEF [O.A.] Weinland, David Friedrich Author: Weinland, David Friedrich Recipient: Haeckel, Ernst Dating: 27.03.1888