Columbia subject headings:
Printing industry--Employees--Labor unions--Italy--Milan--History.
Printing industry--Italy--Milan--History.
Harvard subject headings:
Printing industry--Employees--Labor unions--Italy--Milan--History.
Printing industry--Italy--Milan--History.
Princeton subject headings:
Printing industry--Employees--Labor unions--Italy--Milan--History.
Printing industry--Italy--Milan--History.