Grams, Christian M. http://orcid.org/0000-0003-3466-9389
Beerli, Remo http://orcid.org/0000-0002-0897-9650
Pfenninger, Stefan http://orcid.org/0000-0002-8420-9498
Staffell, Iain http://orcid.org/0000-0003-1012-7075
Wernli, Heini http://orcid.org/0000-0001-9674-4837
Article History
Received: 15 March 2017
Accepted: 13 June 2017
First Online: 17 July 2017
Competing interests
: The authors declare no competing financial interests.