Butkevich, Eugenia
Härtig, Wolfgang
Nikolov, Miroslav
Erck, Christian
Grosche, Jens
Urlaub, Henning
Schmidt, Christoph F.
Klopfenstein, Dieter R.
Chua, John Jia En
Article History
Received: 14 December 2015
Accepted: 11 May 2016
First Online: 1 June 2016
Competing interests
: The authors declare no competing financial interests.