Columbia subject headings:
Holdt, Jacob--Travel--United States.
United States--Social conditions--1960-1980.
United States--Social life and customs--1971-
Harvard subject headings:
Holdt, Jacob--Journeys--United States.
Holdt, Jacob--Travel--United States.
United States--Social conditions--1960-1980.
United States--Social life and customs--1971-
Princeton subject headings:
Poor--United States.
United States--Economic conditions--1981-2001.
United States--Social conditions--1980-2020.