Columbia subject headings:
Illegal aliens--Government policy--United States.
Terrorism--United States--Prevention.
Terrorists--Government policy--United States.
Terrorists--United States--Identification.
United States--Emigration and immigration--Government policy.
Harvard subject headings:
Illegal immigration--Government policy--United States.
Noncitizens--Government policy--United States
Terrorism--United States--Prevention
Terrorists--Government policy--United States.
Terrorists--United States--Identification.
United States--Emigration and immigration--Government policy
Princeton subject headings:
Illegal aliens--Government policy--United States.
Terrorism--United States--Prevention.
Terrorists--Government policy--United States.
Terrorists--United States--Identification.
United States--Emigration and immigration--Government policy.