Columbia subject headings:
Catholic Church. Pope (1963-1978 : Paul VI). Populorum progressio.
Church and social problems--Catholic Church.
Developing countries.
Harvard subject headings:
Princeton subject headings:
Catholic Church. Pope (1963-1978 : Paul VI). Populorum progressio
Economic development--Moral and ethical aspects.
Economic development--Religious aspects--Catholic Church.
Poor--Developing countries.