Text and Data Mining valid from 2019-01-15
Received: 9 October 2018
Accepted: 8 January 2019
First Online: 15 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.