Text and Data Mining valid from 2018-07-03
Received: 18 February 2018
Accepted: 8 June 2018
First Online: 3 July 2018
Compliance with ethical standards
: The authors declare that they have no conflict of interest.
: All procedures performed in this study 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.