BRIEF [O.A.] Dahrenstaedt, Helene Author: Dahrenstaedt, Helene Recipient: Haeckel, Ernst Dating: 20.12.1908
BRIEF [O.A.] Dahrenstaedt, Helene Author: Dahrenstaedt, Helene Recipient: Haeckel, Ernst Dating: 06.02.1908
BRIEF [O.A.] Brabant, W... H... Author: Brabant, W... H... Recipient: Haeckel, Ernst Dating: 09.08.1908