Text and Data Mining valid from 2019-03-01
Received: 9 August 2018
Accepted: 3 February 2019
First Online: 1 March 2019
Compliance with ethical standards
: The authors declare that they have 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 Helsinki declaration and its later amendments or comparable ethical standards.
: Informed consent was obtained from all participants included in the study.