1. V. A. Kovtunenko, Z. V. Voitenko, V. L. Sheptun, and L. I. Savranskii,Ukr. Khim. Zh.,51, 976 (1985).
2. V. A. Kovtunenko, Z. V. Voitenko, L. I. Savranskii, A. K. Tyltin, and F. S. Babichev,Khim. Geterotsikl. Soedin., No. 2, 216 (1988).
3. Yu. V. Zefirov and P. M. Zorkii,Usp. Khim.,64, 446 (1995).
4. H. B. Burgi and J. D. Dunitz,Structure Correlation, Vol. 2, VCH, Weinheim (1994).
5. N. M. Sergeev,NMR Spectroscopy [in Russian], Moskovsk. Gos. Univ., Moscow (1981), p. 91.