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