Text and Data Mining valid from 2019-06-07
Received: 8 May 2019
Accepted: 27 May 2019
First Online: 7 June 2019
Compliance with Ethical Standards
: The authors declare that there is 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 the1964 Helsinki declaration and its later amendments or comparable ethical standards.
: Informed consent was obtained from all individual participants included in the study.