Epidemiology SectionBr Med J 1942; 2 doi: https://doi.org/10.1136/bmj.2.4255.117 (Published 25 July 1942) Cite this as: Br Med J 1942;2:117
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