Text and Data Mining valid from 2019-08-27
Received: 24 May 2019
Accepted: 12 August 2019
First Online: 27 August 2019
Compliance with ethical standards
: The authors declare that they have no conflict of interest.
: All procedures performed in studies involving human participants were in accordance with the ethical standards of a national research committee and with the 1964 Helsinki declaration and its later amendments.
: Informed consent was obtained from all individual participants included in the study.