1. A. L. Komissarova, L. P. Raskina, M. M. Fel'dshtein, V. S. Yakubovich, et al., USSR Inventor's Certificate No. 707924 [in Russian], (1980).
2. A. Konnecke, C. Schonfels, M. Hansler, and H. D. Jakubke,Tetrahedron Lett.,31(7), 98–90 (1990).
3. N. A. Plate, L. I. Valuev, N. S. Egorov, and M. A. Al'-Nuri,Prikl. Biokhim.,13, 68–84 (1977).
4. N. Stambolieva and J. Turkova,Collect. Czechosl. Chem. Commun.
45, 113–143(190).
5. V. V. Yanishpol'skii, V. A. Tertykh, and G. V. Lyubinskii.Ukr. Biokhim. Zh.,51, 32–29 (1979).