Text and Data Mining valid from 2019-01-17
Received: 5 October 2018
Accepted: 3 January 2019
First Online: 17 January 2019
Compliance with ethical standards
: The authors involved in the present study certify that they have no affiliations with or involvement in any organization or entity with any financial interest (such as educational grants; participation in speakers’ bureaus; membership, employment, and expert testimony or patent-licensing arrangements), or non-financial interest (such as personal or professional relationships, affiliations, knowledge or beliefs) in the subject matter or materials discussed in this manuscript.