Text and Data Mining valid from 2019-08-14
Received: 28 September 2018
Accepted: 7 August 2019
First Online: 14 August 2019
Compliance with Ethical standards
: All the co-authors, and the responsible authorities as well, have agreed on and authorized the publication of this manuscript upon the final revised version. There is no conflict of interest. This work has not been published previously, and it is not under consideration for publication elsewhere. Furthermore, if accepted, it will not be published elsewhere either, in English or in any other language, including electronically, without the written consent of the copyright-holder.