Statistics from Altmetric.com
Contributors JK drafted the manuscript and made revisions as suggested by Professor Otto. He is the guarantor. MM revised the draft manuscript.
Competing interests None.
Provenance and peer review Not commissioned; internally peer reviewed.
If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.