Columbia subject headings:
Authors, German--20th century--Correspondence.
Rilke, Rainer Maria, 1875-1926--Correspondence.
Ungern-Sternberg, Rolf, Freiherr von--Correspondence.
Harvard subject headings:
Authors, German--20th century--Correspondence
Rilke, Rainer Maria, 1875-1926. Correspondence
Ungern-Sternberg, Rolf, Freiherr von--Correspondence.
Princeton subject headings:
Authors, German--20th century--Correspondence.
Rilke, Rainer Maria, 1875-1926. Correspondence.
Ungern-Sternberg, Rolf, Freiherr von, 1880-1943--Correspondence.