Funding for this research was provided by:
Text and Data Mining valid from 2019-04-29
Received: 7 August 2018
Accepted: 4 April 2019
First Online: 29 April 2019
Compliance with ethical standards
: The authors declare that they have no conflicts 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.