Text and Data Mining valid from 2019-11-15
Received: 5 August 2019
Accepted: 1 October 2019
First Online: 15 November 2019
Compliance with ethical standards
: The authors declare that they have no conflict of interest.
: All procedures performed in the 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.
: For this type of study, formal consent is not required.