Text and Data Mining valid from 2019-02-05
Received: 1 November 2018
Accepted: 17 December 2018
First Online: 5 February 2019
Compliance with ethical standards
: All authors have no conflicts of interest.
: All procedures 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.