Text and Data Mining valid from 2019-07-13
Received: 25 February 2019
Accepted: 30 May 2019
First Online: 13 July 2019
Compliance with ethical standards
: The authors declare that they have no conflict of interest.
: All procedures performed in this study 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.