Text and Data Mining valid from 2019-04-04
Received: 28 January 2019
Accepted: 31 March 2019
First Online: 4 April 2019
Compliance with ethical standards
: Both authors declare that they have no conflict of interest.
: All procedures performed in this study involving human participants were in accordance with the ethical standards of the 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.