Personal ViewBr Med J 1977; 2 doi: http://dx.doi.org/10.1136/bmj.2.6088.698 (Published 10 September 1977) Cite this as: Br Med J 1977;2:698
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