1. B. Noheda, Curr. Opin. Solid State Mater. Sci. 6, 27 (2002).
2. N. G. Leont’ev, E. G. Fesenko, and V. G. Smotrakov, Sov. Phys. Solid State 25(7), 1130 (1983).
3. E. G. Fesenko, V. V. Eremkin, and V. G. Smotrakov, Sov. Phys. Solid State 28(1), 181 (1986).
4. E. G. Fesenko, V. V. Eremkin, V. G. Smotrakov, S. G. Shmal’ko, and A. T. Kozakov, Sov. Phys. Crystallogr. 32(4), 617 (1987).
5. V. V. Eremkin, V. G. Smotrakov, and E. G. Fesenko, Sov. Phys. Solid State 31(6), 1002 (1989).