Text and Data Mining valid from 2019-01-16
Received: 16 September 2018
Accepted: 6 January 2019
First Online: 16 January 2019
Compliance with ethical standards
: The authors declare that they have no conflict of interest.
: Informed consent was obtained from all participants in the study.
: 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.