Columbia subject headings:
DDT (Insecticide)--Environmental aspects.
DDT (Insecticide)--Toxicology.
Harvard subject headings:
DDT (Insecticide)--Environmental aspects.
DDT (Insecticide)--Toxicology.
Princeton subject headings:
DDT (Insecticide)--Environmental aspects.
DDT (Insecticide)--Toxicology.