Khavkin, E. E.
Article History
Received: 23 June 2020
Revised: 24 June 2020
Accepted: 26 June 2020
First Online: 5 March 2021
COMPLIANCE WITH ETHICAL STANDARDS
: <i>Conflict of interests</i>. The authors declare that they have no conflicts of interest.
: <i>Statement on the welfare of humans or animals</i>. This article does not contain any studies involving animals performed by any of the authors.