Epidemiology SectionBr Med J 1950; 1 doi: http://dx.doi.org/10.1136/bmj.1.4661.1089 (Published 06 May 1950) Cite this as: Br Med J 1950;1:1089
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