Columbia subject headings:
Harvard subject headings:
Internal security--European Union countries--Congresses.
Security, International--European Union countries--Congresses.
Terrorism--European Union countries--Congresses.
Terrorism--European Union countries--Prevention--Congresses.
Princeton subject headings:
Internal security--European Union countries--Congresses.
Security, International--European Union countries--Congresses.
Terrorism--European Union countries--Congresses.
Terrorism--European Union countries--Prevention--Congresses.