EpidemiologyBr Med J 1965; 1 doi: http://dx.doi.org/10.1136/bmj.1.5428.199 (Published 16 January 1965) Cite this as: Br Med J 1965;1:199
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