Text and Data Mining valid from 2019-08-27
Received: 12 April 2019
Accepted: 30 July 2019
First Online: 27 August 2019
Compliance with Ethical Standards
: All authors declare that they have no conflict of interest.
: All procedures performed 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.