BRIEF OHNE UMSCHLAG Radonetz, Eduard Author: Radonetz, Eduard Recipient: Haeckel, Ernst Dating: 01.12.1885
BRIEF [O.A.] Gaedechens, Rudolph Author: Gaedechens, Rudolph Recipient: Haeckel, Ernst Dating: 13.02.1885
ABSCHRIFT Reiß Author: Reiß Recipient: Haeckel, Ernst Corporation: Gesellschaft für Erdkunde Dating: 25.06.1885