Columbia subject headings:
Catholic Church. Pope (1963-1978 : Paul VI). Populorum progressio.
Church and social problems--Catholic Church.
Church and social problems--Mexico.
Mexico--Social conditions.
Harvard subject headings:
Catholic Church. Pope (1963-1978 : Paul VI). Populorum progressio
Church and social problems--Catholic Church
Church and social problems--Mexico.
Mexico--Social conditions.
Princeton subject headings: