Text and Data Mining valid from 2018-09-21
Received: 23 April 2018
Accepted: 21 July 2018
First Online: 21 September 2018
Compliance with Ethical Standards
: The author declares that he has no conflicts of interest to disclose.
: 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.