BRIEF [O.A.] Kleinsorgen, Wilhelm Author: Kleinsorgen, Wilhelm Recipient: Haeckel, Ernst Dating: 23.02.1908
BRIEF [O.A.] Kleinsorgen, Wilhelm Author: Kleinsorgen, Wilhelm Recipient: Haeckel, Ernst Dating: 25.02.1908
POSTKARTE Kleinsorgen, Wilhelm Author: Kleinsorgen, Wilhelm Recipient: Haeckel, Ernst Dating: 31.12.1908
TELEGRAMM Kleinsorgen, Wilhelm Author: Kleinsorgen, Wilhelm Recipient: Haeckel, Ernst Dating: 16.02.1910
BRIEF [O.A.] Kleinsorgen, Wilhelm Author: Kleinsorgen, Wilhelm Recipient: Haeckel, Ernst Dating: 30.07.1910
BRIEF [O.A.] Kleinsorgen, Wilhelm Author: Kleinsorgen, Wilhelm Recipient: Haeckel, Ernst Dating: 04.08.1910
BRIEF [O.A.] Kleinsorgen, Wilhelm Author: Kleinsorgen, Wilhelm Recipient: Haeckel, Ernst Dating: 31.12.1910
BRIEF [O.A.] Kleinsorgen, Wilhelm Author: Kleinsorgen, Wilhelm Recipient: Haeckel, Ernst Dating: 11.02.1911
BRIEF [O.A.] Kleinsorgen, Wilhelm Author: Kleinsorgen, Wilhelm Recipient: Haeckel, Ernst Dating: 15.02.1911
BRIEF [O.A.] Kleinsorgen, Wilhelm Author: Kleinsorgen, Wilhelm Recipient: Haeckel, Ernst Dating: 22.03.1911