Columbia subject headings:
Mobile communication systems--United States.
Telecommunication systems--United States.
Wireless communication systems--United States.
Harvard subject headings:
Mobile communication systems--United States.
Mobile communication systems.
Telecommunication systems--United States.
Telecommunication systems.
Wireless communication systems
Wireless communication systems--United States
Princeton subject headings:
Mobile communication systems--United States.
Telecommunication systems--United States.
Wireless communication systems--United States.