Authors
Andrey Targonskii
Department of Mathematics, Zhitomir State University, Veluka Berdichivska, 40, 10008, Zhitomir, Ukraine
© 2017 Andrey Targonskii, published by Ovidius University of Constanta
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.