Columbia subject headings:
Communication--Research.
Mass media--Japan.
Mass media--United States.
Harvard subject headings:
Book industries and trade--Japan--Statistics.
Book industries and trade--United States--Statistics.
Communication and traffic--Japan--Statistics.
Communication and traffic--United States--Statistics.
Communication--Japan--Statistics.
Communication--United States--Statistics.
Telecommunication--Japan--Statistics.
Telecommunication--United States--Statistics.
Princeton subject headings:
Communication--Research.
Mass media--Japan.
Mass media--United States.