Personal ViewBr Med J (Clin Res Ed) 1983; 286 doi: https://doi.org/10.1136/bmj.286.6378.1646 (Published 21 May 1983) Cite this as: Br Med J (Clin Res Ed) 1983;286:1646
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