Columbia subject headings:
Legal documents--Europe--Identification.
Passports--Europe.
Terrorism--Europe--Prevention.
Tourism--Eruope.
Transportation--Effect of terrorism on--Europe.
Harvard subject headings:
Legal documents--Europe--Identification.
Passports--Europe.
Terrorism--Europe--Prevention
Tourism--Europe
Transportation--Effect of terrorism on--Europe.
Princeton subject headings:
Passports--Europe.
Terrorism--Europe--Prevention.
Tourism--Europe.
Transportation--Effect of terrorism on--Europe.