Columbia subject headings:
Customs administration--United States.
Tariff--Law and legislation--United States.
Taxation--Law and legislation--United States.
Harvard subject headings:
Customs administration--United States.
Tariff--Law and legislation--United States.
Taxation--Law and legislation--United States
Princeton subject headings:
Customs administration--United States.
Tariff--Law and legislation--United States.
Taxation--Law and legislation--United States.