Footnotes

• Correction notice This article has been corrected since it first published. The provenance and peer review statement has been included.

• Contributors The authors confirm their authorship according to the following criteria: have made substantial contributions to conception and design, or acquisition of data or analysis and interpretation of data; been involved in drafting the manuscript or revising it critically for important intellectual content; given final approval of the version to be published; each author should have participated sufficiently in the work to take public responsibility for appropriate portions of the content; and agreed to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. VR confirm that all authors agree on the order in which their names will be listed in the manuscript.

• Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

• Competing interests None declared.

• Provenance and peer review Not commissioned; externally peer reviewed.