1. X. H. Zhou, X. S. Chen, and X. G. Guo, J. Magn. Magn. Mater. 284, 353 (2004).
2. E. S. Demidov, Yu. A. Danilov, V. V. Podolskii, et al., Pisma Zh. Eksp. Teor. Fiz. 83(12), 664 (2006) [JETP Lett. 83, 568 (2006)].
3. Yu. A. Danilov, E. S. Demidov, and Yu. N. Drozdov, Fiz. Tekh. Poluprovodn. 39(1), 8 (2005) [Semiconductors 39, 4 (2005)].
4. M. Menyhard, A. Barna, J. P. Biersack, et al., J. Vac. Sci. Technol. A 13(4), 1999 (1995).
5. Digital Databases of XPS Spectra, XPS International, www.xpsdata.com.