Article History
First Online: 3 March 2018
Compliance with Ethical Standards
:
: No sources of funding were used to assist in the preparation of this article.
: Nele Pattyn, Randy Beulque, and Véronique Cornelissen have no conflicts of interest directly relevant to the content of this review.
: All authors take responsibility for all aspects of the reliability and freedom from bias of the data presented and their discussed interpretation.