Text and Data Mining valid from 2019-02-02
Received: 10 September 2018
Revised: 27 December 2018
Accepted: 10 January 2019
First Online: 2 February 2019
Compliance with ethical standards
: The authors declare that they have no conflicts of interest.
: Informed consent was obtained from all individual participants included in the study.
: 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.