Columbia subject headings:
Portugal--Foreign relations--Spain.
Spain--Foreign relations--Portugal.
Spain--History--Civil War, 1936-1939.
Harvard subject headings:
Portugal--Foreign relations--Spain.
Spain--Foreign relations--Portugal.
Spain--History--Civil War, 1936-1939.
Princeton subject headings:
Portugal--Foreign relations--Spain.
Spain--Foreign relations--Portugal.
Spain--History--Civil War, 1936-1939.