Text and Data Mining valid from 2019-10-29
Received: 29 June 2019
Accepted: 11 October 2019
First Online: 29 October 2019
Compliance with ethical guidelines
: N. Belala, C. Maier, P. Heldmann, M. Schwenk and C. Becker declare that they have no competing interests.
: Written informed consent was obtained from all individual participants included in the study prior to data collection. All procedures performed in this study involving human participants were in accordance with the standards of the ethic committee of the University of Tübingen and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.
: The supplement containing this article is not sponsored by industry.