Text and Data Mining valid from 2019-06-10
Received: 28 January 2019
Accepted: 23 May 2019
First Online: 10 June 2019
Compliance with ethical standards
: All the authors declare that there is no conflict of interest.
: All procedures involving human participants were performed in accordance with the ethical standards of the institutional research committee and with the 1964 Declaration of Helsinki and subsequent amendments or comparable ethical standards.