BRIEF [O.A.] Sethe-Seyberth, Luise Author: Sethe-Seyberth, Luise Recipient: Haeckel, Ernst Dating: 22.10.1875
BRIEF [O.A.] Sethe-Seyberth, Luise Author: Sethe-Seyberth, Luise Recipient: Haeckel, Ernst Dating: 25.05.1903
BRIEF [O.A.] Sethe-Seyberth, Luise Author: Sethe-Seyberth, Luise Recipient: Haeckel, Ernst Dating: 10.03.1907
BRIEF [O.A.] Sethe-Seyberth, Luise Author: Sethe-Seyberth, Luise Recipient: Haeckel, Ernst Dating: 18.03.1907
BRIEF [O.A.] Sethe-Seyberth, Luise Author: Sethe-Seyberth, Luise Recipient: Haeckel, Ernst Dating: 23.09.1912
BRIEF [O.A.] Sethe-Seyberth, Luise Author: Sethe-Seyberth, Luise Recipient: Haeckel, Ernst Dating: 29.09.1912
TELEGRAMM Sethe-Seyberth, Luise Author: Sethe-Seyberth, Luise Recipient: Haeckel, Ernst Dating: 19.02.1904