Text and Data Mining valid from 2019-01-31
First Online: 31 January 2019
Compliance with Ethical Standards
: No sources of funding were used to assist in the preparation of this article.
: Ward Dobbs, Michael Fedewa, Hayley MacDonald, Clifton Holmes, Zackary Cicone, Daniel Plews and Michael Esco declare that they have no conflicts of interest relevant to the content of this review.