BRIEF [O.A.] Haeckel, Heinrich Author: Haeckel, Heinrich Recipient: Haeckel, Ernst Dating: 27.06.1908
BRIEF [O.A.] Haeckel, Heinrich Author: Haeckel, Heinrich Recipient: Haeckel, Ernst Dating: 07.03.1908
BRIEF [O.A.] Haeckel, Heinrich Author: Haeckel, Heinrich Recipient: Haeckel, Ernst Dating: 15.02.1908
BRIEF [O.A.] Haeckel, Heinrich Author: Haeckel, Heinrich Recipient: Haeckel, Ernst Dating: 01.01.1908
BRIEF [O.A.] Haeckel, Heinrich Author: Haeckel, Heinrich Recipient: Haeckel, Ernst Dating: 24.12.1908
BRIEF [O.A.] Haeckel, Heinrich Author: Haeckel, Heinrich Recipient: Haeckel, Ernst Dating: 28.11.1908