Columbia subject headings:
Geographical location codes.
Tax returns--United States--Data processing.
United States--Administrative and political divisions--Statistics.
United States. Internal Revenue Service--Records and correspondence.
Harvard subject headings:
Geographical location codes.
Tax returns--United States--Data processing.
United States--Administrative and political divisions--Statistics.
United States. Internal Revenue Service--Records and correspondence.
Princeton subject headings:
Geographical location codes.
Statistics.
Tax returns--United States--Data processing.
United States--Administrative and political divisions--Statistics.
United States. Internal Revenue Service--Records and correspondence.