Columbia subject headings:
United States--Foreign relations--1945-1989.
Vietnam War, 1961-1975--United States.
Harvard subject headings:
United States--Foreign relations--1945-
United States--Foreign relations--1945-1989.
Vietnam War, 1961-1975--United States
Princeton subject headings:
United States--Foreign relations--1945-1989.
Vietnam War, 1961-1975--United States.