Note 5 — CHEMICAL EXAMINATION.
Reading edition
83Chamot, E. M., and Pratt, D. S. A study on the phenoldisulfonic acid method for the determination of nitrates in water: J. Am. Chem. Soc., Vol. 31, pp. 922–8, 1909; Vol. 32, pp. 630–7, 1910; and Redfield, H. W., Vol. 33, pp. 366–81, 381–4, 1911.