Funding for this research was provided by:
Text and Data Mining valid from 2019-10-15
Received: 21 May 2019
Accepted: 2 October 2019
First Online: 15 October 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. For this type of study, formal consent is not required.
: Informed consent was obtained from all individual participants included in the study.