Columbia subject headings:
Harvard subject headings:
Electronic data processing--Security measures--European Union countries.
Espionage--European Union countries.
Information warfare--European Union countries.
Intelligence service--European Union countries.
Telecommunication--Defense measures--European Union countries.
Princeton subject headings:
Electronic data processing--Security measures--European Union countries.
Espionage--European Union countries.
Information warfare--European Union countries.
Intelligence service--European Union countries.
Telecommunication--Defense measures--European Union countries.