1. A. F. Pozharskii, A. D. Garnovskii, and A. M. Simonov, Usp. Khim., 35, 261 (1966).
2. Outline of Azole Chemistry [in Russian], Izd. RGU, Rostov-on-Don (1966).
3. A. N. Kost and I. I. Grandberg, Advances in Heterocyclic Chemistry, Vol. 6, New York (1966), p. 347.
4. V. I. Minkin, O. A. Osipov, and Yu. A. Zhdanov, Dipole Moments in Organic Chemistry [in Russian], Leningrad (1968).
5. S. A. Giller, I. B. Mazheika, and I. I. Grandberg, Khim. Geterotsikl. Soedin., 103 (1965).