Columbia subject headings:
Middle class--Political activity--Spain--Congresses.
Revolutions--Spain--History--19th century--Congresses.
Spain--History--19th century--Congresses.
Harvard subject headings:
Middle class--Political activity--Spain--Congresses.
Middle class--Spain--Political activity--Congresses.
Revolutions--Spain--History--19th century--Congresses.
Spain--History--19th century--Congresses.
Princeton subject headings:
Middle class--Spain--Political activity--Congresses.
Revolutions--Spain--History--19th century--Congresses.
Spain--History--19th century--Congresses.