Columbia subject headings:
Criminal justice, Administration of--European Union countries.
Emigration and immigration law--European Union countries.
Freedom of movement--European Union countries.
Internal security--European Union countries.
Harvard subject headings:
Criminal justice, Administration of--European Union countries.
Emigration and immigration law--European Union countries.
Freedom of movement--European Union countries
Internal security--European Union countries
Princeton subject headings:
National security--European Union countries.