Columbia subject headings:
Harvard subject headings:
Agriculture and state--Environmental aspects--United States.
Agriculture and state--United States.
Agriculture--Environmental aspects
Agriculture--Environmental aspects--United States
Pesticide residues in food.
Produce trade--Government policy--United States
United States--Commercial treaties.
Princeton subject headings:
Agriculture--Environmental aspects.
Pesticide residues in food.
Produce trade--Government policy--United States.
United States--Commercial treaties.