Hann, Alexander http://orcid.org/0000-0001-8035-3559
Bettac, Lucas
Haenle, Mark M.
Graeter, Tilmann
Berger, Andreas W.
Dreyhaupt, Jens
Schmalstieg, Dieter
Zoller, Wolfram G.
Egger, Jan
Article History
Received: 16 May 2017
Accepted: 20 September 2017
First Online: 6 October 2017
Competing Interests
: The authors declare that they have no competing interests.