Text and Data Mining valid from 2019-05-20
First Online: 20 May 2019
Compliance with Ethical Standards
: Panos Panagiotopoulos, Nikolaos Maniadakis, George Papatheodoridis and Dimitris Pektasidis declare they have no conflicts of interest with respect to the contents of this article.
: The authors received no specific funding for this study.