Text and Data Mining valid from 2019-02-19
Received: 8 July 2018
Accepted: 29 September 2018
First Online: 19 February 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.