Semeniuk, O.
Juska, G.
Oelerich, J.-O.
Wiemer, M.
Baranovskii, S. D.
Reznik, A.
Article History
Received: 15 February 2016
Accepted: 25 August 2016
First Online: 15 September 2016
Competing interests
: The authors declare no competing financial interests.