1. P. É. Rozentsveig and Yu. K. Sander, Technology of Drugs and Galenicals [in Russian], Leningrad (1967), p. 371.
2. A. G. Daragan, Investigation of Coating by Films Made from Polymeric Film-Forming Compounds [in Russian], Doctoral Dissertation, Moscow (1967).
3. Yu. K. Sander, Data of the Second International Conference of Pharmacists [in Russian], Moscow (1961), p. 154.
4. K. Münzel, Pharm. Acta Helf., Vol. 38 (1963), p. 129.
5. S.Ahsan Sayed, S. M. Blaugh, and D. A. Chakravarty, Drug Stand., Vol. 26 (1958), p. 29.