https://www.bmj.com/content/371/bmj.m4425
https://www.bmj.com/content/371/bmj.m4425/rr-31
Thanks to The British Medical Journal
https://www.bmj.com/content/371/bmj.m4425
https://www.bmj.com/content/371/bmj.m4425/rr-31
Thanks to The British Medical Journal