Text and Data Mining valid from 2019-09-07
Received: 21 April 2019
Accepted: 2 September 2019
First Online: 7 September 2019
Compliance with ethical standards
: The authors of this paper have no conflicts of interest, including specific financial interests, relationships, and/or affiliations relevant to the subject matter or materials included.
: All procedures performed in the study 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.