1. Chaney, R.L. Plant accumulation of heavy metals and phytotoxicity resulting from utilization of sewage sludge composts on cropland. National Conference on Composting of Municipal Residues and Sludges. Rockville: USDA.
2. Davis, R.D. and Stark, J.H. Effects of sewage sludge on the heavy metals content of soils and crops. Field trials at Carrington and Royston. Proceedings of the Second European Symposium Characterization, Treatment and Use of Sewage Sludge. Vienna. In
3. Delcarte, D., Xanthoulis, C. and Impens, R. Valorisation agricole des boues. Problèmes liés a la. présence de métaux lourds. Proceedings of the First European Symposium C.E.E. Treatment and Use of Sewage Sludge. France: Cadarache. (in French)
4. Growth and Metal Uptake of Snap Beans Grown on Sewage Sludge‐Amended Soil: A Four‐Year Field Study