Columbia subject headings:
Environmental law--United States.
Natural resources--Law and legislation--United States.
Harvard subject headings:
Environmental law--United States
Environmental protection--Moral and ethical aspects--United States.
Natural resources--Law and legislation--United States
Nature conservation--Law and legislation--United States.
Nature conservation--Moral and ethical aspects--United States.
Princeton subject headings:
Environmental law--United States.
Natural resources--Law and legislation--United States.