Text and Data Mining valid from 2019-03-22
Received: 26 July 2018
Revised: 23 October 2018
Accepted: 20 February 2019
First Online: 22 March 2019
Compliance with ethical standards
: The authors declare no known conflicts of interest, financial or otherwise, associated with this publication and there has been no significant financial support for this work that could have influenced its outcome.