1. Lacy, P.H. and Smith, D.C.C., J. Chem. Soc. C, 1971, p. 747.
2. Pozharskii, A.F. and Dal’nikovskaya, V.V., Usp. Khim., 1981, vol. 50, p. 1559.
3. Pozharskii, A.F., Vinokurova, T.I., and Zaletov, V.G., Khim. Geterotsikl. Soedin., 1976, p. 539.
4. Vinokurova, T.I. and Pozharskii, A.F., Khim. Geterotsikl. Soedin., 1976, p. 545.
5. Shelepin, O.E., Khimiya peritsiklicheskikh soedinenii (Chemistry of Pericyclic Compounds), Rostov-on-Don: Izd. RGU, 1973, p. 240.