Columbia subject headings:
Harvard subject headings:
Arno River Valley (Italy)--Politics and government--20th century.
Coal miners--Italy--Arno River Valley--History--20th century.
Labor unions--Italy--Arno River Valley--History--20th century.
Princeton subject headings:
Arno River Valley (Italy)--History--20th century.
Arno River Valley (Italy)--Politics and government--20th century.
Miners--Labor unions--Italy--Arno River Valley--History--20th century.