1. Annual book of ASTM standards; soil and rock dimension stone geosynthetics; Vol. 4.08 . (1991). ASTM Philadelphia Pa.
2. Bell C. F. (1977). Principles and applications of metal chelation . Oxford Chemistry Ser. Oxford Univ. Press Oxford England.
3. Multiple-site adsorption of Cd, Cu, Zn, and Pb on amorphous iron oxyhydroxide
4. Cline S. R. (1993). “Efficiencies of soil washing/flushing solutions to remediate lead contaminated soils ” MS thesis Dept. of Civ. and Envir. Engrg. West Virginia Univ. Morgantown W.Va.
5. Kennedy J. B. and Neville A. M. (1986). Basic statistical methods for engineers and scientists . Harper and Row Publishers New York N.Y.