Matura, S
Fleckenstein, J
Deichmann, R
Engeroff, T
Füzéki, E
Hattingen, E
Hellweg, R
Lienerth, B
Pilatus, U
Schwarz, S
Tesky, V A
Vogt, L
Banzer, W
Pantel, J
Article History
Received: 16 December 2016
Revised: 21 April 2017
Accepted: 8 May 2017
First Online: 18 July 2017
Competing interests
: The authors declare no conflict of interest.