Text and Data Mining valid from 2017-01-17
Received: 12 April 2016
Accepted: 4 January 2017
First Online: 17 January 2017
Compliance with Ethical Standards
: The authors declare no potential conflict of interest with respect to the research, authorship and/or publication of this article.
: 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.