Research Article

Students from Queen's University.

Br Med J (Clin Res Ed) 1983; 286 doi: https://doi.org/10.1136/bmj.286.6363.441 (Published 05 February 1983) Cite this as: Br Med J (Clin Res Ed) 1983;286:441

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

PDF extract preview