Tsvetkov, Vladimir B.
Varizhuk, Anna M.
Pozmogova, Galina E.
Smirnov, Igor P.
Kolganova, Natalia A.
Timofeev, Edward N.
Article History
Received: 2 July 2015
Accepted: 13 October 2015
First Online: 17 November 2015
Competing interests
: The authors declare no competing financial interests.