Columbia subject headings:
Presidents--United States--History--20th century--Sources.
United States--Politics and government--20th century--Sources.
Harvard subject headings:
Presidents--United States--History--20th century--Sources.
United States--Politics and government--20th century--Sources.
Princeton subject headings:
Presidents--United States--History--20th century--Sources.
United States--Politics and government--20th century--Sources.