1. Lopyrev, V.A., Larina, L.I., Rakhmatulina, T.N., Shibanova, E.F., Vakulskaya, T.I., Voronkov, M.G.: Dokl. Akad. Nauk SSSR 242 (1978) 142.
2. Dohrmann, J.K., Kieslich, W.: J. Magn. Reson. 32 (1978) 353.
3. Lopyrev, V.A., Larina, L.I., Vakul'skaya, T.I., Shibanova, E.F., Titova, I.A., Voronkov, M.G.: Magn. Resonance Chem. 23 (1985) 305.
4. Baumane, L., Gavars, R., Stradins, J., Chupakhin, O.N., Rusinov, V.L., Petrov, A.Y.: Khim. Geterotsikl. Soedin. 1985, 689.
5. Makarov, I.G., Kazakova, V.M., Zhil'tsov, V.V., Minina, N.E., Traven, V.F., Eismont, M.Y.: Dokl. Akad. Nauk SSSR 276 (1984) 1177.