Text and Data Mining valid from 2019-07-12
Received: 19 April 2019
Accepted: 28 June 2019
First Online: 12 July 2019
Compliance with Ethical Standards
: The authors declare that they have no conflict of interest.
: ll 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. For this type of study formal consent is not required.
: Informed consent was obtained from all individual participants included in the study.