Columbia subject headings:
Agriculture and state--Italy--Po River Plain--History.
Land tenure--Italy--Po River Plain--History.
Landowners--Italy--Po River Plain--History.
Rent--Italy--Po River Plain--History.
Tenant farmers--Italy--Po River Plain--History.
Harvard subject headings:
Agriculture--Social aspects--Italy--Po River Plain--History.
Princeton subject headings:
Agriculture and state--Italy--Po River Plain--History.
Land tenure--Italy--Po River Plain--History.
Land tenure--Law and legislation--Italy--History.
Landowners--Italy--Po River Plain--History.
Rent--Italy--Po River Plain--History.
Tenant farmers--Italy--Po River Plain--History.