1. F. Gimblett and C. Monk, Trans. Faraday Soc. 50, 965 (1954).
2. V. A. Pchelin, Measurement of the Activity of Hydrogen Ions, (State Light Ind. Press, Moscow, 1955), p. 9.
3. A. I. Shatenshtein, Theory of Acids and Bases, Goskhimizdat, (Moscow and Leningrad, 1949), p. 53.
4. A. I. Shatenshtein, loc. cit., p. 106.
5. F. Jones, Z. analyt. Chem. 43, 184 (1904).