Columbia subject headings:
International cooperation--History--20th century--Sources.
Security, International--History--20th century--Sources.
Harvard subject headings:
European federation--History--20th century--Sources.
International cooperation--History--20th century--Sources.
North Atlantic Treaty Organization
Security, International--History--20th century--Sources.
Treaties.
Princeton subject headings:
International cooperation--History--20th century--Sources.
Security, International--History--20th century--Sources.