Columbia subject headings:
Catholics--Northern Ireland--Derry--History--20th century.
Civil rights--Northern Ireland--Derry--History--20th century.
Derry (Northern Ireland)--Politics and government.
Harvard subject headings:
Derry (Northern Ireland)--History.
Irish question--History--20th century.
Irish unification question.
Northern Ireland--History--1968-1998.
Political violence--Northern Ireland--History--20th century
Social conflict--Northern Ireland--History--20th century.
Violence--Northern Ireland--History--20th century.
Princeton subject headings:
Irish question--History--20th century.
Northern Ireland--History--1968-1998.
Violence--Northern Ireland--History--20th century.