Text and Data Mining valid from 2019-08-29
Received: 25 April 2019
Accepted: 3 August 2019
First Online: 29 August 2019
Compliance with Ethical Standards
: The authors declare that they have no conflict of interest.
: All procedures performed during this study involving human participants were in accordance with the ethical standards of the institutional and national research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards.
: For this type of study, informed consent is not required.