KARTE Haeckel, Ernst Franz Max Author: Haeckel, Ernst Franz Max Recipient: Haeckel, Ernst Dating: 13.02.1904
BRIEF [O.A.] Haeckel, Ernst Franz Max Author: Haeckel, Ernst Franz Max Recipient: Haeckel, Ernst Dating: 23.12.1904
BRIEF [O.A.] Haeckel, Ernst Franz Max Author: Haeckel, Ernst Franz Max Recipient: Haeckel, Ernst Dating: 29.12.1904
TELEGRAMM Sethe-Seyberth, Luise Author: Sethe-Seyberth, Luise Recipient: Haeckel, Ernst Dating: 19.02.1904
BRIEF [O.A.] Haeckel, Siegfried Author: Haeckel, Siegfried Recipient: Haeckel, Ernst Dating: ??.??.1904