Columbia subject headings:
Harvard subject headings:
Catholic Church. Pope (1878-1903 : Leo XIII). Rerum novarum.
Church and social problems--Catholic Church--Papal documents.
Church and state--Italy--Modena--History.
Labor--Religious aspects--Christianity--Italy--Modena.
Modena (Italy)--Church history.
Modena (Italy)--Social conditions.
Opera dei Congressi e dei comitati cattolici in Italia--History.
Princeton subject headings:
Catholic Church--Italy--Modena--History.
Church and social problems--Italy--Modena--History--19th century.
Cooperation--Italy--Modena--History--19th century.