Received: 9 July 2019
Accepted: 26 February 2020
First Online: 28 May 2020
Ethics approval and consent to participate
: The ethics committee of the University of Graz has approved this study (GZ 39/58/63 ex 2016/17). Consent to participate was obtained from each participant (minimum age was 18 years) in written form.
: Not applicable.
: The authors declare that they have no competing interests.