Text and Data Mining valid from 2019-02-04
Received: 6 June 2018
Accepted: 28 January 2019
First Online: 4 February 2019
Compliance with ethical standards
: KA Brocker reports personal fees by Serag Wiessner, Naila, Germany, outside the submitted work. All the other authors declare that they have no conflict of interest.
: All procedures performed in this trial involving human participants were in accordance with the ethical standards of the institutional research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards. This article does not contain any studies with animals performed by any of the authors.
: Informed consent was obtained from all individual participants included in the study.