Vallelian, F
Deuel, J W
Opitz, L
Schaer, C A
Puglia, M
Lönn, M
Engelsberger, W
Schauer, S
Karnaukhova, E
Spahn, D R
Stocker, R
Buehler, P W
Schaer, D J
Article History
Received: 7 April 2014
Revised: 4 August 2014
Accepted: 21 August 2014
First Online: 10 October 2014
Competing interests
: The authors declare no conflict of interest.