Hädrich, Steffen
Klenke, Arno
Rothhardt, Jan
Krebs, Manuel
Hoffmann, Armin
Pronin, Oleg
Pervak, Vladimir
Limpert, Jens
Tünnermann, Andreas
Article History
Received: 17 March 2014
Accepted: 28 July 2014
First Online: 14 September 2014
Competing interests
: The authors declare no competing financial interests.