1. Gutlich, P., Struct. Bond, Berlin: Springer, 1981, vol. 44, p. 83.
2. König, E., Ritter, G., and Kulshreshtha, S.K., Chem. Rev., 1985, vol. 85, no. 3, p. 219.
3. Kolle, V., Ang. Chem. Int. Ed., 1991, vol. 30, no. 8, p. 956.
4. Zelentsov, V.V., Koord. Khim., 1992, vol. 18, no. 8, p. 788.
5. Lavrenova, L.G. and Larionov, S.V., Koord. Khim., 1998, vol. 24, no. 6, p. 403 [Russ. J. Coord. Chem. (Engl. Transl.), vol. 24, no. 6, p. 379].