Research Article
Epidemiology for the uninitiated. Aetiology of disease--selection of controls.
Br Med J 1978; 2 doi: https://doi.org/10.1136/bmj.2.6152.1616 (Published 09 December 1978) Cite this as: Br Med J 1978;2:1616This is a PDF-only article. The first page of the PDF of this article appears above.