Text and Data Mining valid from 2019-04-09
Received: 12 December 2018
Accepted: 15 March 2019
First Online: 9 April 2019
Compliance with ethical standards
: The authors declare that they have no conflict of interest.
: All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. In Germany, in the case of studies only involving questionnaires on general topics, a formal approval from a research ethics committee is not required.
: All individual participants included in the study were informed about protection of their data and voluntariness of the participation and gave their consent.