Columbia subject headings:
Harvard subject headings:
Ireland--Politics and government--20th century.
Irish unification question.
Nationalism--Ireland--History--20th century
Northern Ireland--Politics and government--1968-1998.
Princeton subject headings:
Ireland--Politics and government--20th century.
Irish unification question.
Nationalism--Ireland--History--20th century.
Northern Ireland--Politics and government--1968-1998.