1. L. S. Maiofis, Chemistry and Technology of Pharmaceutical Products [in Russian], Leningrad (1964), p. 382.
2. K. M. Saldadze, A. B. Pashkov, and V. S. Titov, Ion-ExchangeHigh-Molecular Compounds [in Russian], Moscow (1960), p. 85.
3. State Pharmacopeia of the USSR [in Russian], IX Edition, Moscow (1961), p. 327.
4. Chemical Handbook [in Russian], Vol. 3, B. P. Nikol'skii (editor), Moscow (1964), p. 102.