Funding for this research was provided by:
Text and Data Mining valid from 2020-02-01
Received: 30 October 2019
Accepted: 6 January 2020
First Online: 3 February 2020
Compliance with ethical standards
: All 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 national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.
: Informed consent was obtained from all individual participants included in the study.