Text and Data Mining valid from 2017-09-16
First Online: 16 September 2017
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.
: Informed consent was obtained from all individual participants included in the study.
: The authors declared no conflicts of interest with respect to the authorship or the publication of this article.