Columbia subject headings:
Harvard subject headings:
Great Britain--Colonies--History--19th century.
Great Britain--Colonies--History--20th century.
Imperialism--History--19th century
Imperialism--History--20th century
Princeton subject headings:
Great Britain--Colonies--History--19th century.
Great Britain--Colonies--History--20th century.
Imperialism--History--19th century.
Imperialism--History--20th century.