1. D. M. Freїk, M. O. Galushhak, A. І. Tkachuk, Prykarp. vіsn. NTSh 1(13), 137 (2011)
2. M. O. Haluschak, V. G. Ralchenko, A. I. Tkachuk, Phys. Chem. Sol. State 14, 317 (2013)
3. Springer Handbook of Materials Measurement Methods, edited by H. Czichos, T. Saito, L. Smith (Sturtz AG, Würzburg, 2006);
4. D. M. Freїk, R. Ja. Mihajl'onka, V. M Klanіchka, Fіz. Khіm. Tverd. Tіla 5, 173 (2004)
5. A. D. Stuskes, R. P. Shasmar, J. Appl. Phys. 30, 930 (1959)