1. Kolthoff I. M., Belcher R. (1957) Volumetric Analysis, Vol. 3. Interscience, New York
2. Wilson C. L., Wilson D. W. (eds.) (1960) Comprehensive Analytical Chemistry, Vol. 1 B. Elsevier, Amsterdam
3. British Standards 1121, Part 38 (1967)
4. Arnold J. P., Johnson R. M. (1969) Talanta16: 1191
5. Kolthoff I. M., Probst R. L. (1949) Anal. Chem.21: 753