Schmier, Sonja
Mostafa, Ahmed
Haarmann, Thomas
Bannert, Norbert
Ziebuhr, John
Veljkovic, Veljko
Dietrich, Ursula
Pleschka, Stephan
Article History
Received: 25 November 2014
Accepted: 27 May 2015
First Online: 19 June 2015
Competing interests
: The authors declare no competing financial interests.