Funding for this research was provided by:
Text and Data Mining valid from 2018-05-30
Received: 4 April 2018
Accepted: 22 May 2018
First Online: 30 May 2018
Compliance with ethical standards
: The authors have no conflict of interest to declare.
: This study was conducted in accordance with the principles of the Declaration of Helsinki and written informed consent was obtained from all participants prior to participation. The local ethics committee of the University of Graz, Austria, approved the study.