Personal ViewBr Med J (Clin Res Ed) 1984; 289 doi: https://doi.org/10.1136/bmj.289.6439.248 (Published 28 July 1984) Cite this as: Br Med J (Clin Res Ed) 1984;289:248
Log in using your username and password
Log in through your institution
Register for a free trial to thebmj.com to receive unlimited access to all content on thebmj.com for 14 days.
Sign up for a free trial