Columbia subject headings:
Music--20th century--History and criticism--Congresses.
Zimmermann, Bernd Alois, 1918-1970--Congresses.
Harvard subject headings:
Instrumental music--20th century--History and criticism--Congresses.
Zimmermann, Bernd Alois, 1918-1970--Criticism and interpretation--Congresses.
Princeton subject headings:
Instrumental music--20th century.--History and criticism.
Zimmermann, Bernd Alois, 1918-1970--Criticism and interpretation.