Sturm, Gunnar
Richter, Katrin
Doetsch, Andreas
Heide, Heinrich
Louro, Ricardo O
Gescher, Johannes
Article History
Received: 2 July 2014
Revised: 24 November 2014
Accepted: 5 December 2014
First Online: 30 January 2015
Competing interests
: The authors declare no conflict of interest.