Text and Data Mining valid from 2018-09-19
Received: 4 August 2018
Accepted: 13 September 2018
First Online: 19 September 2018
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 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.