Columbia subject headings:
Invoices--United States.
Telecommunication--Taxation--Law and legislation--United States.
Telephone--Law and legislation--United States.
Telephone--Taxation--Law and legislation--United States.
Harvard subject headings:
Invoices--United States.
Telecommunication--Taxation--Law and legislation--United States.
Telephone--Law and legislation--United States
Telephone--Taxation--Law and legislation--United States.
Princeton subject headings:
Invoices--United States.
Telecommunication--Taxation--Law and legislation--United States.
Telephone--Law and legislation--United States.
Telephone--Taxation--Law and legislation--United States.