1. N. T. Bagraev, A. I. Gusarov, and V. A. Mashkov, Sov. Phys. JETP 65(3), 548 (1987).
2. A. Goltzené, Rev. Phys. Appl. 22, 469 (1987).
3. V. A. Grazhulis and Yu. A. Osip’yan, Sov. Phys. JETP 33, 623 (1971).
4. M. Brohl, C. Kisielowski-Kemmerich, and H. Alexander, Appl. Phys. Lett. 50, 1733 (1987).
5. E. R. Weber and H. Alexander, J. Phys., Colloq. 44, C4–319 (1983).