Jungnickel, C
Schmidt, L H
Bittigkoffer, L
Wolf, L
Wolf, A
Ritzmann, F
Kamyschnikow, A
Herr, C
Menger, M D
Spieker, T
Wiewrodt, R
Bals, R
Beisswenger, C
Article History
Received: 27 May 2016
Revised: 7 December 2016
Accepted: 9 January 2017
First Online: 27 March 2017
Competing interests
: The authors declare no conflict of interest.