Bogatyrev, A. B. http://orcid.org/0000-0002-9581-4554
Funding for this research was provided by:
RAS Program “Fundamental mathematics and its applications” (PRAS-18-01)
Article History
Received: 13 October 2018
Revised: 13 January 2019
Accepted: 28 January 2019
First Online: 13 February 2019
Compliance with ethical standards
:
: The author declares that he has no conflict of interest.