1. W. Jark, S. Di Fonzo, G. Soullie, et al., J. Alloys Compd. 286, 9 (1999).
2. T. A. Bobrova and L. I. Ognev, in Abstracts of the International Conference Current Status of Synchrotron Radiation in the World, Moscow, 2000, p. 54.
3. S. V. Kukhlevsky, G. Lubkovics, K. Negrea, and L. Kozma, Pure Appl. Opt. 6, 97 (1997).
4. T. A. Bobrova and L. I. Ognev, Pis’ma Zh. Éksp. Teor. Fiz. 69, 686 (1999) [JETP Lett. 69, 734 (1999)].
5. T. A. Bobrova and L. I. Ognev, Phys. Status Solidi B 203(2), R11 (1997).