Columbia subject headings:
Harvard subject headings:
Demonstrations--Northern Ireland--Derry.
Derry (Northern Ireland)--History.
Ireland.
Princeton subject headings:
Bloody Sunday, Derry, Northern Ireland, 1972.
Demonstrations--Northern Ireland--Derry--History--20th century.
Derry (Northern Ireland)--History.
Political violence--Northern Ireland--Derry--History--20th century.