Text and Data Mining valid from 2019-01-06
Received: 22 September 2018
Accepted: 20 December 2018
First Online: 6 January 2019
Compliance with Ethical Standards
: The authors declare 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 Declaration of Helsinki and its later amendments or comparable ethical standards.
: Informed consent was obtained from all individual participants included in the study.