Schwarzer, R
Nickel, N
Godau, J
Willie, B M
Duda, G N
Schwarzer, R
Cirovic, B
Leutz, A
Manz, R
Bogen, B
Dörken, B
Jundt, F
Article History
Received: 23 April 2014
Accepted: 30 April 2014
First Online: 13 June 2014
Competing interests
: The authors declare no conflict of interest.