Research Article

Protecting confidentiality.

Br Med J (Clin Res Ed) 1984; 288 doi: http://dx.doi.org/10.1136/bmj.288.6424.1102 (Published 14 April 1984) Cite this as: Br Med J (Clin Res Ed) 1984;288:1102

This is a PDF-only article. The first page of the PDF of this article appears below.

PDF extract preview