Columbia subject headings:
United States--Foreign relations--1933-1945.
United States--Foreign relations--1945-1989.
United States--Foreign relations--1989-1993.
United States--Foreign relations--1993-2001.
Harvard subject headings:
United States--Foreign relations--1933-1945
United States--Foreign relations--1945-1989
United States--Foreign relations--1989-
Princeton subject headings: