V. E. Fedorov
Chelyabinsk State University, Mathematical Analysis Department; South Ural State University, Laboratory of Functional Materials
Russian Federation

Vladimir E. Fedorov

Chelyabinsk State University, Mathematical Analysis Department, 129 Brothers Kashirin Street, Chelyabinsk 454021, Russia;

South Ural State University, Laboratory of Functional Materials, 76 Lenin Avenue, Chelyabinsk 454080, Russia 

K. V. Boyko
Chelyabinsk State University, Mathematical Analysis Department
Russian Federation

Kseniya V. Boyko,

Chelyabinsk State University, Mathematical Analysis Department, 129 Brothers Kashirin Street, Chelyabinsk 454021, Russia 

T. D. Phuong
Institute of Mathematics of the Vietnamese Academy of Science and Technology, Department of Numerical Analysis and Scientific Computing
Viet Nam

Ta D. Phuong,

Institute of Mathematics of the Vietnamese Academy of Science and Technology, Department of Numerical Analysis and Scientific Computing, Hanoi, Vietnam