Text and Data Mining valid from 2019-02-04
Received: 14 January 2019
Accepted: 16 January 2019
First Online: 4 February 2019
Compliance with ethical standards
: The authors declare that they have no conflict of interest.
: All procedures performed in the 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.