1. A. I. Tentsova and I. G. Azhgikhin, Farmatsiya (1970).
2. G. Kedvessy, I. Abdelhady, and J. Morvey, Pharmazie,30, 476 (1975).
3. B. V. Nazarov and E. F. Seleznev, Nauchn. Tr. Permsk. Farm. Inst., No. 5, Part 2, 70 (1973).
4. G. Levy, Am. J. Pharm.,135, 78 (1963).
5. H. J. Groves, Csl. Farm.,22, 137 (1973).