Columbia subject headings:
Harvard subject headings:
Labor laws and legislation--Spain--Zaragoza--History--Sources.
Legal instruments--Spain--Zaragoza.
Occupations--Spain--Zaragoza--History--Sources.
Social legislation--Spain--Zaragoza--History--Sources.
Working class--Spain--Zaragoza--History--Sources.
Zaragoza (Spain)--Economic conditions--Sources.
Zaragoza (Spain)--Social conditions--Sources.
Princeton subject headings:
Working class--Spain--Zaragoza--History--Sources.
Zaragoza (Spain)--Economic conditions.
Zaragoza (Spain)--History--Sources.
Zaragoza (Spain)--Social conditions.