Columbia subject headings:
United States--Civilization--1970-
United States--Economic conditions--1961-1971.
United States--Politics and government--1945-1989.
Harvard subject headings:
United States--Civilization--1970-
United States--Economic conditions--1981-2001.
United States--Politics and government--1945-1989.
Princeton subject headings:
United States--Civilization--1970-
United States--Economic conditions--1961-.
United States--Politics and government--1945-1989.