Abd-Elgawad, Mahfouz M. M. http://orcid.org/0000-0002-4731-5988
Funding for this research was provided by:
Institute of Mathematics, National Academy of Sciences of RA
Article History
Received: 11 April 2020
Accepted: 25 May 2020
First Online: 5 June 2020
Ethics approval and consent to participate
: Not applicable
: Not applicable
: The author declares that he has no competing interests.