BRIEF [O.A.] Bechhold, Heinrich Author: Bechhold, Heinrich Recipient: Haeckel, Ernst Dating: 05.01.1909
BRIEF [O.A.] Bechhold, Heinrich Author: Bechhold, Heinrich Recipient: Haeckel, Ernst Dating: 23.02.1909
BRIEF [O.A.] Recipient: Haeckel, Ernst Corporation: Senckenbergische Naturforschende Gesellschaft Dating: 07.04.1909
BRIEF [O.A.] Schreiner, Friedrich Author: Schreiner, Friedrich Recipient: Haeckel, Ernst Dating: 11.11.1909