SUPPLEMENTBr Med J 1970; 4 doi: https://doi.org/10.1136/bmj.4.5738.67 (Published 26 December 1970) Cite this as: Br Med J 1970;4:67
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