Funding for this research was provided by:
The Russian Science Foundation (16-14-10155)
Text and Data Mining valid from 2018-10-23
Received: 14 July 2018
Accepted: 8 October 2018
First Online: 23 October 2018
Ethics approval and consent to participate
: Not applicable.
: The authors declare that they have no competing interests.
: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.