1. Georgakopoulos, I.P. , Mitronikas E.D. ,Safacas, A.N.R.R. Schoen, et al.: IEEE Trans. on Industry Electronics, Vol. 58-. 9(2011), p.4365.
2. Garcia-Perez A., Jesus Romero-Troncoso R., Cabal-Yepez, E.: IEEE Transactions on Industrial Electronics, Vol. 58-5(2011), p. (2002).
3. Hyun C. C., Knowles, J., Fadali, M.S. : IEEE Trans. On Control Systems Technology , Vol. 18-2(2010) p.430.
4. Niao Q. H., Lu R. X., Feng S, G.: IEEE Trans. On Instrumentation and Measurement, Vol. 60-2(2011)p.480.
5. Faiz, J. , Ebrahimi, B.M., Akin, B.: IEEE Trans. On Magnetics, Vol. 44-1(2008) p.66.