Columbia subject headings:
Medievalism--History--20th century.
Music--20th century--History and criticism.
Harvard subject headings:
Francis, of Assisi, Saint, 1182-1226--Songs and music.
Guillaume, de Machaut, approximately 1300-1377.
Medievalism--History--20th century.
Music--20th century--History and criticism
Music--500-1400--History and criticism
Princeton subject headings:
Medievalism--History--20th century.
Music--20th century--History and criticism.