Columbia subject headings:
Harvard subject headings:
Border patrols--Mexican-American Border Region.
Illegal immigration--Government policy--United States.
Noncitizens--Government policy--United States
Operation Gatekeeper (U.S.)--Evaluation.
U.S. Border Patrol
Princeton subject headings:
Border patrols--California--San Diego.
Border patrols--Mexican-American Border Region.
Illegal aliens--California--San Diego.
Illegal aliens--Government policy--United States.
Operation Gatekeeper (U.S.)--Evaluation.
U.S. Border Patrol.