1. A. G. Fogg, D. R. Marriott, D. T. Burns,Analyst 1970,95, 848.
2. D. F. Wood, R. T. Clark,Analyst 1958,83, 326.
3. Z. Marczenko,Separation and Spectrophotometric Determination of Elements, Ellis-Horwood, Chichester, 1986, pp. 604?605.
4. H. Onishi,Photometric Determination of Traces of Metals, Wiley, 1989, pp. 588?593.
5. K. Yoshimura, H. Waki,Talanta 1985,32, 345.