1. T. Dietl, Nature Mater. 9, 965 (2010).
2. A. V. Komarov, S. M. Ryabchenko, O. V. Terletskii, et al., Sov. Phys. JETP 46, 318 (1977).
3. J. Schneider, U. Kaufmann, W. Wilkening, et al., Phys. Rev. Lett. 59, 240 (1987).
4. V. F. Masterov, S. B. Mikhrin, B. E. Samorukov, et al., Sov. Phys. Semicond. 17, 796 (1983).
5. A. Abragam and B. Bleaney, Electron Paramagnetic Resonance of Transition Ions (Oxford Univ. Press, Oxford, 1970).