Columbia subject headings:
Harvard subject headings:
United States--Politics and government--1969-1974.
United States--Politics and government--1974-1977.
United States--Politics and government--1977-1981.
Princeton subject headings:
United States--Politics and government--1969-1974.
United States--Politics and government--1974-1977.
United States--Politics and government--1977-1981.