1. L. E. Nikitina, O. A. Shkuro, and V. V. Plemenkov, Zh. Org. Khim., 29, 1794 (1993).
2. L. E. Nikitina, Doctoral Dissertation, Kaz. Gos. Med. Univ., Kazan, 2002, 330 pp.
3. O. A. Shkuro, Candidate Dissertation, Kaz. Gos. Med. Univ., Kazan, 1996, 118 pp.
4. V. V. Plemenkov, Introduction to the Chemistry of Natural Compounds [in Russian], MPIK, Kazan, 2001, 376 pp.
5. L. E. Nikitina, O. A. Shkuro, and V. V. Plemenkov, Chem. Nat. Compd., 30, 223 (1994).