Pyatkov, Felix
Fütterling, Valentin
Khasminskaya, Svetlana
Flavel, Benjamin S.
Hennrich, Frank
Kappes, Manfred M.
Krupke, Ralph
Pernice, Wolfram H. P.
Article History
Received: 18 May 2015
Accepted: 15 March 2016
First Online: 18 April 2016
Competing interests
: The authors declare no competing financial interests.