Columbia subject headings:
Portugal--History--19th century.
Portugal--Relations--Spain.
Spain--History--19th century.
Spain--Relations--Portugal.
Harvard subject headings:
Iberian Peninsula--History--19th century.
Nationalism--Portugal--History--19th century.
Nationalism--Spain--History--19th century.
Portugal--History--19th century.
Spain--History--19th century
Princeton subject headings:
Nationalism--Portugal--19th century.
Nationalism--Spain--19th century.