Columbia subject headings:
Africa--Economic conditions.
Africa--History--19th century.
Africa--History--20th century.
Africa--Social conditions.
Harvard subject headings:
Africa--Economic conditions.
Africa--History--19th century.
Africa--History--20th century.
Africa--Social conditions.
Princeton subject headings:
Africa--Economic conditions.
Africa--History--19th century.
Africa--History--20th century.
Africa--Social conditions.