Funding for this research was provided by:
Text and Data Mining valid from 2019-01-10
First Online: 10 January 2019
Compliance With Ethical Standards
: The authors declare they have no conflicts 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.
: Informed consent was obtained from all individual participants included in the study.