Text and Data Mining valid from 2018-10-08
Received: 16 July 2018
Accepted: 5 September 2018
First Online: 8 October 2018
Compliance with ethical standards
: The authors declare that they do not have any conflict of interest that may inappropriately influence this work.
: This article is a review article of published literature and does not contain any original study with human participants or animals performed by any of the authors.
: For this type of study formal consent is not required.