Columbia subject headings:
Composers--Germany--Correspondence.
Nietzsche, Friedrich Wilhelm, 1844-1900.
Philosophers--Germany--Correspondence.
Wagner, Richard, 1813-1883.
Harvard subject headings:
Composers--Germany--Correspondence
Nietzsche, Friedrich Wilhelm, 1844-1900
Philosophers--Germany--Correspondence
Wagner, Richard, 1813-1883
Princeton subject headings: