Columbia subject headings:
Harvard subject headings:
Competition, International.
Market surveys.
Water pollution control equipment industry--United States.
Water pollution control equipment industry.
Water purification equipment industry--United States.
Water purification equipment industry.
Water resources development--United States--Equipment and supplies.
Princeton subject headings:
Competition, International.
Market surveys.
Water pollution control equipment industry--United States.
Water pollution control equipment industry.
Water purification equipment industry--United States.
Water purification equipment industry.