1. Report prepared by commission on Microchemical Techniques and Trace Analysis, IUPAC, Pure and Appl. Chem., 59 (1987) 695.
2. Report prepared by the Analytical Working Group of the Comité Technique Européen du Fluor, Anal. Chim. Acta., 182 (1986) 1.
3. M. S. FRANT, J. W. ROSS, Anal. Chem., 40 (1968) 1169.
4. M. A. MAHAJAN, M. V. R. PRASAD, R. M. SAWANT, R. K. RASTOGI, N. K. CHAUDHURI, G. H. RIZVI, BARC/I-920, 1987.
5. R. BELCHER, T. S. WEST, Talanta, 8 (1961) 863.