Columbia subject headings:
Depletion allowances--Law and legislation--United States.
Depletion allowances--United States.
Gas and gas companies--Taxation--United States.
Natural gas--Taxation--United States.
Petroleum law and legislation--Taxation--United States.
Petroleum--Taxation--Law and legislation--United States.
Petroleum--Taxation--United States.
Harvard subject headings:
Depletion allowances--Law and legislation--United States.
Natural gas--Taxation--United States.
Petroleum--Taxation--Law and legislation--United States
Princeton subject headings:
Depletion allowances--Law and legislation--United States.
Natural gas--Taxation--United States.
Petroleum--Taxation--Law and legislation--United States.