Columbia subject headings:
Air--Pollution--Economic aspects.
Environmental policy--Cost effectiveness.
Environmental protection--Cost effectiveness.
Water--Pollution--Economic aspects.
Harvard subject headings:
Air--Pollution--Economic aspects
Environmental policy--Cost effectiveness
Environmental protection--Cost effectiveness
Water--Pollution--Economic aspects.
Princeton subject headings:
Air--Pollution--Economic aspects.
Environmental policy--Cost effectiveness.
Environmental protection--Cost effectiveness.
Water--Pollution--Economic aspects.