Columbia subject headings:
Eavesdropping--United States--Statistics--Periodicals.
Electronic surveillance--United States--Statistics--Periodicals.
Wiretapping--United States--Statistics--Periodicals.
Harvard subject headings:
Princeton subject headings:
Eavesdropping--United States--Statistics--Periodicals.
Electronic surveillance--United States--Statistics--Periodicals.
Periodicals.
Statistics.
Wiretapping--United States--Statistics--Periodicals.