Footnotes

• Contributors Beatriz Gosalbez revised the paper

• 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.

• Patient consent for publication Not required.

• Ethics approval This article does not contain any studies with human participants performed by any of the authors.

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