Text and Data Mining valid from 2019-09-03
Received: 9 February 2019
Accepted: 17 July 2019
First Online: 3 September 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 amendments or comparable ethical standards.
: No funding was received.
: Informed consent was obtained from all individual participants included in the study.