Author Contributions
All authors substantially conceived and designed concept, structure and
design of the review, provided important intellectual input, contributed
considerably to the analyses and interpretation of the data and have
been involved in re-drafting the manuscript. CV, BB and MJ
counter-checked the literature search, BB evaluated the methodology in
the reviewed papers. All authors critically revised the manuscript and
gave final approval of the version to be published. No honorarium,
grant, or other form of payment was given to any of the authors to
produce this manuscript.