Text and Data Mining valid from 2019-07-05
Received: 5 June 2019
Accepted: 1 July 2019
First Online: 5 July 2019
Compliance with ethical standards
: The authors declare that they have no conflict of interest.
: This manuscript has not been published and is not under consideration for publication elsewhere. Its publication is approved by all authors.
: This article does not contain any studies with human or animal subjects performed by any of the authors.
: If accepted, it will not be published elsewhere in the same form, in English or any other language, including electronically without the written consent of the copyright holder.