Text and Data Mining valid from 2018-04-30
Received: 12 April 2018
Accepted: 25 April 2018
First Online: 30 April 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.
: This article does not contain any studies with animals performed by any of the authors.
: Informed consent was obtained from all individual participants included in the study.