Columbia subject headings:
Acid deposition--Environmental aspects--United States.
Acid precipitation (Meteorology)--Environmental aspects--United States.
Harvard subject headings:
Acid deposition--Environmental aspects--United States.
Acid deposition--United States.
Acid precipitation (Meteorology)--Environmental aspects--United States.
Acid precipitation (Meteorology)--United States.
Princeton subject headings:
Acid deposition--Environmental aspects--United States.
Acid precipitation (Meteorology)--Environmental aspects--United States.