Columbia subject headings:
Green products--Economic aspects--United States--Statistics.
Green technology--Economic aspects--United States--Statistics.
Pollution control equipment industry--United States--Statistics.
Pollution control industry--United States--Statistics.
Harvard subject headings:
Green products--Economic aspects--United States--Statistics.
Green technology--Economic aspects--United States--Statistics.
Pollution control equipment industry--United States--Statistics.
Pollution control industry--United States--Statistics.
Princeton subject headings:
Green products--Economic aspects--United States--Statistics.
Green technology--Economic aspects--United States--Statistics.
Pollution control equipment industry--United States--Statistics.
Pollution control industry--United States--Statistics.
Statistics.