Document is current

Article History

Received: 19 July 2018

Accepted: 28 November 2018

First Online: 14 December 2018

Competing interest

: The authors declare that they have no competing interests.

: The study was approved by the ethics committee of the University of Bielefeld.In both the paper-and-pencil and the online version, the first page explained the purpose of the study, the kind of questions that would follow, the anonymity of the data and data storage security. Participants agreed either by sending the questionnaires back (paper and pencil) or by checking the ‘I accept’ box in the online version.

: ‘Not applicable’.

: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.