Text and Data Mining valid from 2018-12-12
Received: 19 July 2018
Revised: 14 November 2018
Accepted: 9 December 2018
First Online: 12 December 2018
Compliance with ethical standards
: All 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 individual participants included in the study.