Text and Data Mining valid from 2019-03-08
Received: 21 August 2018
Accepted: 1 March 2019
First Online: 8 March 2019
Compliance with Ethical Standards
: The authors declare that we 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.
: Informed consent was obtained from all individual participants included in the study.