Columbia subject headings:
Authors, German--19th century--Correspondence.
Authors, German--20th century--Correspondence.
Love-letters--History--20th century.
Mynona, 1871-1946--Correspondence.
Philosophers--Germany--Correspondence.
Schwinghoff, Luise Marie, 1883-1968--Correspondence.
Harvard subject headings:
Authors, German--19th century--Correspondence
Authors, German--20th century--Correspondence
Love-letters--History--20th century.
Mynona, 1871-1946--Correspondence.
Philosophers--Germany--Correspondence
Schwinghoff, Luise Marie, 1883-1968--Correspondence.
Princeton subject headings:
Authors, German--19th century--Correspondence.
Authors, German--20th century--Correspondence.
Love-letters--History--20th century.
Mynona, 1871-1946--Correspondence.
Philosophers--Germany--Correspondence.
Schwinghoff, Luise Marie, 1883-1968--Correspondence.