Funding for this research was provided by:
Russian Science Foundation (17-77-20070)
Text and Data Mining valid from 2020-03-18
Received: 29 December 2019
Accepted: 9 March 2020
First Online: 18 March 2020
Ethics approval and consent to participate
: Not applicable.
: All authors have given their consent for this publication.
: The authors declare that they have no competing interests.