BRIEF [O.A.] Steman, Friedrich Author: Steman, Friedrich Recipient: Haeckel, Ernst Dating: 03.08.1919
BRIEF OHNE UMSCHLAG Steman, Friedrich Author: Steman, Friedrich Recipient: Haeckel, Ernst Dating: 08.02.1900
BRIEF [O.A.] Steman, Friedrich Author: Steman, Friedrich Recipient: Haeckel, Ernst Dating: 12.11.1913
BRIEF [O.A.] Steman, Friedrich Author: Steman, Friedrich Recipient: Haeckel, Ernst Dating: 15.02.1914
BRIEF [O.A.] Steman, Friedrich Author: Steman, Friedrich Recipient: Haeckel, Ernst Dating: 28.03.1914
BRIEF [O.A.] Steman, Friedrich Author: Steman, Friedrich Recipient: Haeckel, Ernst Dating: 03.05.1914