D.G. Kovtun, A.M. Khegay, A.G. Shein, D.L. Yeskin

P.D. Kravchenya  Post-graduant Student, Department of Physics Volgograd State Technical University (VSTU)
A.G. Shein  D.Sc. (Phys.-Math.), Professor, Department of Physics Volgograd State Technical University (VSTU)