Demidov, V. E.
Urazhdin, S.
Zholud, A.
Sadovnikov, A. V.
Slavin, A. N.
Demokritov, S. O.
Article History
Received: 13 November 2014
Accepted: 27 January 2015
First Online: 26 February 2015
Competing interests
: The authors declare no competing financial interests.