Text and Data Mining valid from 2019-11-01
Received: 25 July 2019
Accepted: 9 October 2019
First Online: 20 November 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 research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.