Columbia subject headings:
Harvard subject headings:
English drama--20th century--History and criticism--Congresses.
English drama--Irish authors--History and criticism--Congresses.
Irish drama--History and criticism--Congresses.
Theater--Ireland--History and criticism--Congresses.
Princeton subject headings:
English drama--20th century--History and criticism--Congresses.
English drama--Irish authors--History and criticism--Congresses.
Irish drama--History and criticism--Congresses.
Theater--Ireland--History and criticism--Congresses.