Columbia subject headings:
Nietzsche, Friedrich Wilhelm, 1844-1900.
Wagner, Richard, 1813-1883.
Harvard subject headings:
Music--Philosophy and aesthetics
Nietzsche, Friedrich Wilhelm, 1844-1900--Criticism and interpretation.
Philosophy, German.
Wagner, Richard, 1813-1883--Criticism and interpretation.
Princeton subject headings:
Nietzsche, Friedrich Wilhelm, 1844-1900.
Wagner, Richard, 1813-1883.