Columbia subject headings:
Music--20th century--History and criticism.
Music--21st century--History and criticism.
Harvard subject headings:
Music--20th century--History and criticism--Congresses.
Music--20th century--Political aspects--Congresses.
Music--21st century--History and criticism--Congresses.
Princeton subject headings:
Music--20th century--History and criticism.
Music--21st century--History and criticism.