1. Atanasova, I. (1987) Thesis (Sofia University, Sofia, Bulgaria).
2. Bontchev, P. R., Mitewa, M., Nefedov, V. I., and Salyn, Ya. E. (1986)Proceedings, XXIV International Conference on Coordination Chemistry, Athens, Greece, Aug., p. 720.
3. Bontchev, P. R., Mitewa, M., Gencheva, G., Macicek, J., Angelova, O., and Nefedov, V. I. (1987)Proceedings, llth Conference on Coordination Chemistry, Smolenice, CSSR, June, p. 37.
4. Martin-Gil, F. J., and Martin-Gil, J. (1987)Inorg. Chim. Acta 137, 131.
5. Mitewa, M., Gencheva, G., Bontchev, P. R., Angelova, O., and Macicek, J. (1988)Polyhedron 7, 1273.