Columbia subject headings:
Drama--Technique--History--Congresses.
European drama--History and criticism--Congresses.
Music in the theater--History--Congresses.
Theater--Europe--History--Congresses.
Harvard subject headings:
Drama--Technique--History--Congresses.
European drama--History and criticism--Congresses.
Music in the theater--History--Congresses.
Music in the theaters--History--Congresses.
Theater--Europe--History--Congresses.
Princeton subject headings:
Drama--Technique--History--Congresses.
European drama--History and criticism--Congresses.
Music in the theater--History--Congresses.
Theater--Europe--History--Congresses.