BRIEF [O.A.] Heilmann, Eva (geb. Hahn) Author: Heilmann, Eva (geb. Hahn) Recipient: Haeckel, Ernst Dating: 16.02.1919
BRIEF [O.A.] Haeckel, Siegfried Author: Haeckel, Siegfried Recipient: Haeckel, Ernst Dating: 15.02.1919
BRIEF [O.A.] Jaeger, Mabel (geb. Bleek) Author: Jaeger, Mabel (geb. Bleek) Recipient: Haeckel, Ernst Dating: 14.02.1919