Text and Data Mining valid from 2018-08-23
First Online: 23 August 2018
Compliance with Ethical Standards
: There were no conflicts of interest in this study.
: 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.