Text and Data Mining valid from 2019-03-30
Received: 23 January 2019
Accepted: 20 March 2019
First Online: 30 March 2019
Compliance with ethical standards
: The authors declare that they have no conflict of interest.
: No financial support was received for this study.
: This study was carried out in accordance with the Helsinki Declaration and informed consent was obtained from all the participants involved in the study.