Columbia subject headings:
Iron and steel workers--Italy--Arno River Valley--History--19th century--Sources.
Iron industry and trade--Italy--Arno River Valley--History--19th century--Sources.
Iron industry and trade--Social aspects--Italy--Arno River Valley--History--19th century--Sources.
Pareto, Vilfredo, 1848-1923.
Sociologists--Italy--Correspondence.
Harvard subject headings:
Iron and steel workers--Italy--Arno River Valley--History--19th century--Sources.
Iron industry and trade--Italy--Arno River Valley--History--19th century--Sources.
Iron industry and trade--Social aspects--Italy--Arno River Valley--History--19th century--Sources.
Pareto, Vilfredo, 1848-1923.
Sociologists--Italy--Correspondence.
Princeton subject headings:
Iron industry and trade--Italy--Tuscany--History.
Pareto, Vilfredo, 1848-1923.