1. V. A. Devyatnin, Methods of Chemical Analysis and Manufacture of Vitamins [in Russian], Moscow (1964).
2. F. Kritchfield, Analysis of the Basic Functional Groups in Organic Compounds [Russian translation], Moscow (1965).
3. T. C. Bruice and J. Bruno, J. Amer. Chem. Soc.,83, 3494 (1961).
4. Houben-Weil, Methods of Organic Chemistry (Methods of Analysis) [Russian translation], Moscow (1963), p. 505.
5. N. Midzukami, J. Pharm. Soc. Jap.,76, 1129 (1956).