Columbia subject headings:
Catholic Church. Pope (1878-1903 : Leo XIII). Rerum novarum.
Catholic Church. Pope (1978-2005 : John Paul II). Centesimus annus.
Christian sociology--Catholic Church--Papal documents.
Christian sociology--Catholic Church.
Harvard subject headings:
Catholic Church. Pope (1878-1903 : Leo XIII). Rerum novarum.
Catholic Church. Pope (1978-2005 : John Paul II). Centesimus annus.
Christian sociology--Catholic Church--Papal documents.
Christian sociology--Catholic Church.
Princeton subject headings: