Columbia subject headings:
European Union countries--Defenses.
European Union countries--Foreign relations.
National security--European Union countries.
Security, International--European Union countries.
Harvard subject headings:
European Union countries--Defenses.
European Union countries--Foreign relations.
National security--European Union countries
Security, International--European Union countries
Princeton subject headings:
European Union countries--Defenses.
European Union countries--Foreign relations.
National security--European Union countries.
Security, International--European Union countries.