Text and Data Mining valid from 2018-07-03
Received: 1 February 2018
Revised: 19 June 2018
Accepted: 20 June 2018
First Online: 3 July 2018
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 the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. The study described has been carried out in accordance with the abovementioned standards and has been approved by the institutional ethic committee.
: Informed consent was obtained from all individual participants included in the study.