1. E. B. Sandell, Colorimetric Determination of Traces of Metals, 3rd ed. New York: Interscience. 1959. p. 754
2. E. B. Sandell, Colorimetric Determination of Traces of Metals, 3rd ed. New York: Interscience. 1959. p. 756
3. E. B. Sandell, Colorimetric Determination of Traces of Metals, 3rd ed. New York: Interscience. 1959. p. 757
4. E. B. Sandell, Colorimetric Determination of Traces of Metals, 3rd ed. New York: Interscience. 1959. p. 648
5. E. B. Sandell, Colorimetric Determination of Traces of Metals, 3rd ed. New York: Interscience. 1959. p. 755.