Columbia subject headings:
Schumann, Robert, 1810-1856--Correspondence.
Schumann, Robert, 1810-1856--Friends and associates.
Harvard subject headings:
Composers--Germany--Correspondence
Schumann, Clara, 1819-1896--Correspondence.
Schumann, Robert, 1810-1856--Correspondence.
Princeton subject headings:
Schumann, Robert, 1810-1856--Correspondence.