1. A. A. Proskurnikov et al., Metrol. Izmer. Tekh., No. 4, All-Union Scientific-Research Institute of Technical Information, Classification, and Coding (VNIIKI), Moscow (1974).
2. P. S. Tutund?i?, Anal. Chim. Acta,18, No. 1 and 2 (1958).
3. J. Marinenko and J. K. Taylor, Anal. Chem.,40, No. 11 (1968).
4. F. A. Cooper and J. C. Quayle, Analyst,91, No. 1083 (1966).
5. W. F. Koch et al., Talanta,22, No. 9 (1975).