Research Article
A post-Christmas carol.
Br Med J (Clin Res Ed) 1981; 282 doi: https://doi.org/10.1136/bmj.282.6263.549 (Published 14 February 1981) Cite this as: Br Med J (Clin Res Ed) 1981;282:549This is a PDF-only article. The first page of the PDF of this article appears above.