Text and Data Mining valid from 2019-06-13
Received: 6 September 2018
Accepted: 4 June 2019
First Online: 13 June 2019
Compliance with Ethical Standards
: All of the study authors declare that 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.