Columbia subject headings:
Harvard subject headings:
Aragon (Spain)--Economic conditions--Sources.
Aragon (Spain)--Social conditions--Sources.
Sociedad Económica Aragonesa de Amigos del País--History--Sources.
Princeton subject headings:
Aragon (Spain)--Economic conditions--Sources.
Aragon (Spain)--Social conditions--Sources.
Sociedad Económica Aragonesa de Amigos del País--History--Sources.