Text and Data Mining valid from 2019-01-29
Received: 7 September 2018
Revised: 26 November 2018
Accepted: 28 November 2018
First Online: 29 January 2019
Compliance with ethical standards
: All 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.
: The authors declare that they have no conflict of interest.
: Informed consent was taken.