Vassilev, T. L.
Starkina, O. V.
Article History
Received: 11 April 2019
Revised: 13 May 2019
Accepted: 15 May 2019
First Online: 18 October 2019
COMPLIANCE WITH ETHICAL STANDARDS
: The authors declare that they have no conflict of interest. This article does not contain any studies involving humans or animals as experimental objects.