Text and Data Mining valid from 2019-09-05
Received: 23 May 2019
Revised: 19 August 2019
Accepted: 27 August 2019
First Online: 5 September 2019
Compliance with Ethical Standards
: The authors confirm that there are no known conflicts of interest associated with this publication and there has been no significant financial support for this work that could have influenced its outcome.