Wang, Da
Galla, Hans-Joachim
Drücker, Patrick
Article History
Received: 5 October 2017
Accepted: 13 December 2017
First Online: 4 January 2018
Compliance with ethical standards
:
: Da Wang declares that he has no conflict of interest. Hans-Joachim Galla declares that he has no conflict of interest. Patrick Drücker declares that he has no conflict of interest.
: This article does not contain any studies with human participants or animals performed by any of the authors.