1. Woodwell, G. M., Effects of pollution on the structure and physiology of ecosystems. Science, 168 (1970) 429–33.
2. Carson, R. L., Silent Spring. Houghton Mifflin, Boston, 1962.
3. Barker, J., Notes on some ecological effects of DDT sprayed on elms. 7. Wildl. Management, 22 (1958) 569–74.
4. Davis, B. N. K., Laboratory studies on the uptake of dieldrin and DDT by earthworms. Soil Biol. Biochem., 3 (1971) 221–33.
5. Dimond, J. B., Belyea, G. Y. Kadunce, R. E., Getchell, A. S. & Blease, J. A., DDT residues in robins and earthworms associated with contaminated forest soils. Can. Entomol., 102 (1970) 1112–30.