Columbia subject headings:
Authors and theater--Congresses.
Drama--History and criticism--Congresses.
Playwriting--Congresses.
Harvard subject headings:
Authors and theater--Congresses.
Drama--History and criticism--Congresses
Playwriting--Congresses.
Princeton subject headings:
Authors and theater--Europe--Congresses.
European drama--19th century--History and criticism--Congresses.
European drama--20th century--History and criticism--Congresses.