1) E. B. Sandell, H. Onishi : "Photometric Determination of Traces of Metals : General Aspects", 4th Ed., p. 711 (1978), (Wiley-Interscience, New York).
2) 横須賀 繁 : 分化, 4,509(1955).
3) E. B. Sandell : "Colorimetric Determination of Traces of Metals", 3rd Ed., p. 522 (1959), (Interscience, New York).
4) I. M. Kolthoff, E. B. Sandell, E. J. Meehan, S. Bruckenstein : "Quantitative Chemical Analysis", 4th Ed., p. 588 (1969), (Macmillan, London).