Columbia subject headings:
Herbicides--Environmental aspects--United States.
Herbicides--Toxicology--United States.
Pesticides--Environmental aspects--United States.
Pesticides--Toxicology--United States.
Harvard subject headings:
Herbicides--Environmental aspects--United States.
Herbicides--Toxicology--United States.
Pesticides--Environmental aspects--United States
Pesticides--Toxicology--United States.
Princeton subject headings:
Herbicides--Environmental aspects--United States.
Herbicides--Toxicology--United States.
Pesticides--Environmental aspects--United States.
Pesticides--Toxicology--United States.