Gunin, A. G.
Golubtzova, N. N.
Article History
Received: 9 October 2018
Revised: 9 November 2018
Accepted: 14 November 2018
First Online: 13 September 2019
COMPLIANCE WITH ETHICAL STANDARDS
: The authors declare that they have no conflict of interest. The study was approved by the Ethics Committee of the Medical faculty of Ulianov Chuvash State University.