Columbia subject headings:
Spain--Economic conditions--20th century.
Spain--Population--History--20th century.
Spain--Social conditions--20th century.
Harvard subject headings:
Spain--Economic conditions--20th century.
Spain--Population--History--20th century.
Spain--Social conditions--20th century.
Princeton subject headings:
Spain--Economic conditions--20th century.
Spain--Population--History--20th century.
Spain--Social conditions--20th century.