Penzkofer, Michael http://orcid.org/0000-0003-2009-2064
Seefelder, Stefan
Heuberger, Heidi http://orcid.org/0000-0003-1046-010X
Article History
Received: 16 November 2017
Accepted: 3 April 2018
First Online: 6 April 2018
Compliance with ethical standards
:
: The authors declare that they have no competing interests.