Text and Data Mining valid from 2019-02-22
Received: 8 November 2018
Accepted: 18 February 2019
First Online: 22 February 2019
Compliance with ethical standards
: The authors declare that there is no conflict of interest regarding the 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 1975 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.