1. ABBOTT, R.A.: Metals in Municipal Sewage Systems. Water Resources Commission 1971.
2. BARTH, E.F., M.B. ETTINGER, B.V. SALOTTO, and G.N. McDERMOTT: J. Water Poll. Contr. Fed.37, 86 (1965).
3. FRIEDMAN, M., and A.C. WAISS: Environ. Sci. Tech.6, 47 (1972).
4. GHOSH, M.M., and P.D. ZUGGER: J. Water Poll. Contr. Fed.45, 425 (1973).
5. KING, W.G., J.M. RODRIGUEZ, and C.M. WAI: Anal. Chem.46, 771 (1974).